Multiple values in a google sheet cell

As I’m trying to build a data base using google sheets (which in some ways seems much more cooler due to the possibility to add scripts ) I got into a bit of a pickle.

It seems that softr dosen’t read up multiple values in a single cell ( I used to do that with air table lookup feature to store multiple emails as applicants to a event)
Since I can’t seem to do the same with google sheets I really cant find a way to filter who can see the event or not.

My goal would be that once a user applies to the event that event disappears from the view of that particular user as it’s no longer relevant in the event list.

Any work arounds or things I might have missed ? I do feel like a mokey with a stick right now