This feature shouldn't be implemented on the server side or decided by the front end code, as the developers would have to decide which "same names" to merge. It's the end user who should pick that.
It would better be a front end/app feature: The end user would pick communities from multiple servers (even ones with different names), and group them under whatever name/category they want. The front end would then show all posts/comments from that group as they were from a single community.
Additional feature: Automatically merge comments from cross-posts.
https://feddit.nl/post/458654
vlemmy.net stopped working (or stopped being useable) yesterday.
The domain was showing as parked in a dynamic dns server.
Nobody knows what happened so far.