Changing post depending upon where you’re redirected from?

This will require a bit of coding. The best way to do this with the use of query paramters. You’ll need to add some query paramters to the end of each of your links. Then, on the landing page, check the query paramaters (which should have different values depending on which link you clicked) and display the content based on the vlaues in the query string.

Heres a resource to help you get started: https://stackoverflow.com/questions/11442180/getting-querystring-parameter-value-in-wordpress