How can you override the is_multisite check in wp-login.php for individual login/registration?

Related Posts:

1. How can I un-reserve a pending username registration?
2. Is there a is_user_logged_in() for multisite?
3. wordpress multisite, how to keep user on subdomain throughout registration process?
4. Allowing periods in usernames
5. Remove Site Name from register form – Multisite
6. Unable to login to new custom domain on multisite?
7. share login/logout sessions across two installs?
8. How to Login Once to an Entire WP Multisite Network
9. Prevent user creating new users with specific roles
10. Get first_name and last_name on user_register hook
11. Can’t add user to blog on registration (Multisite)
12. Is there a wordpress function to cleanly delete an entry in the signups table?
13. Multisite – Redirect All Users to Subsite Home Page on Subsite Login
14. WordPress 3.2(Multisite) – How to add custom user meta fields to signup form?
15. How to add multiple existing users to a multisite site?
16. WordPress Multisite Login Access
17. WPMU – new users are automatically subscribed to the main blog – how to prevent that?
18. Subdomain login problems
19. User registration on sub site
20. WordPress Multisite local: wp-login.php refreshes on login Chrome Browser
21. ‘Remote Login’ with MultiSite Domain Mapping still forcing users to login to all blogs individually?
22. How to stay logged in on a multisite with different domains?
23. Disable domain redirect
24. Login on Multiple Sub-Domains without Multisite
25. Fresh Multisite Install – Can’t Log In
26. Displaying a message upon user registration
27. Auto Redirect after login
28. What sites are you registered to when joining a multisite?
29. WordPress MultiSite login to the respective site
30. Add a user to a specific blog when they register?
31. Auto creation of multisite blog on user registration
32. Multisite – user email activation links broken
33. Add menu items/actions for multisite users who are registered on the network but do not have a role or capability in any sites
34. Four columns in the wp_users table
35. How to fix blocked cookies error that doesn’t let me log into wp-admin?
36. WP MU Register User across all blogs
37. Is the Multi site functionality a viable option for Country and Language targeting?
38. Good way to block users within a multisite setup without deleting them?
39. Using the standard WordPress “New User” interface on a multisite
40. Automatically login user across multisite
41. How to write RewriteRule for login in multisite
42. User registration on two sites in same multisite
43. Multisite Login problem
44. How to change a user role after registering in multisite?
45. Https and Http Login Issue on WordPress Multisite
46. Different Domains in Multisite Setup
47. How to fix that new users show up again in subsite of a Multisite?
48. Multisite infinite redirect loop
49. Disable site visiting and user logins excepting for a specific user
50. User registration is currently not allowed
51. Infamous admin login redirect
52. Multisite ‘Welcome User Email’ SITE_NAME returns ‘network’ name, not the name of the blog
53. Is there something I need to know in order to use WordPress on foreign (Swedish) TLDs?
54. Restrict users of site 1 to login in site 2 in wordpress multisite
55. Unable to execute Ajax request, status code 400
56. How to display custom logo on WordPress login page
57. User registration on wordpress multisite
58. Easily adding multiple existing users to a multisite site
59. Moving from a non WordPress site to a WordPress Site – Login between both sites
60. Automatic registration on main site upon user registration on Multisite
61. Register a user only to the root blog – WP Multisite
62. Activate User account for Sub Site broken
63. Possible to have duplicate usernames on different two multisites
64. How to allow mixed case characters in multisite site name?
65. Modify new user email notification in network admin screen wp multisite
66. WordPress Multisite: Login to all subsites at once
67. Users getting linked unwanted to main mu in WordPress multisite (WPMU)
68. Multisite – site user limited only for this site
69. Unable to sign in to network after moveing address but able to login into child sites
70. User not staying logged into one of sub sites in multisite after SSL
71. Can’t activate a user on multisite install
72. WordPress Multisite Network Subdomain
73. Single sign on to sub-sites in Multisite Network
74. WordPress automatic Login on other page?
75. Multisite: How to bypass wpmu_signup_user_notification and add my own notification logic?
76. how to make a cronjob run, when user needs to be logged in
77. Allow users to register on multisite through WooCommerce using the same email address
78. A different role for each site in a multisite
79. WordPress Network with SSL for multiple domains
80. Why does this multisite redirection loop vanish when I add “www.”?
81. Activation of new Registered site fails on multisite
82. One login for 3 WordPress installations with combined user table doesn’t work
83. User registration problem on multisites web
84. Multisite “Skip Confirmation Email” Log Out Problem
85. Multisite – User creation for second site from first site?
86. How to Create WPMu New User?
87. Multisite: Redirect Subsite Administrator to Subsite Home Page, Bypassing Dashboard
88. Admin user getting redirected to /wp-admin/user
89. How to login a user with wp_set_auth_cookie on a specific blog within a multisite environment
90. Possible to set new user’s site time zone at user creation using Gravity Forms?
91. multisite registration: check existing subdomains while typing
92. Is it possible to create a login for restricted visibility?
93. How do I combine wp_redirect and add_filter?
94. Some Subdomains on a Multisite Install Not Found
95. Common login for websites belonging in different networks
96. Registration Page
97. Using a number for limiting registering or banning on multisite
98. How to use same email for multiple users? [duplicate]
99. Best Way to Setup a Network of WP Sites?
100. WordPress Multisite restict user access