There are some flaws in the architecture as you’ve described it, but it may well be too far along for you to change that. If it’s not, it would make more sense to extend the built-in user feature and just add the additional fields you need for that user.
If it’s too far along for that, my recommendation would be to loop through the blog posts on an item that matches a field on the CPT.
For example, you could query_posts using author_name (if the employee CPT name matches) or you could do a custom $wpdb->query and loop through the posts where the email address or name or something similar matches.
But if I had a choice, I would go back and start over with extending the built in user functionality instead of using a CPT for it.