Multiple Asignee Fields & Notifications

Dear YouTrack-Team, 

I want to include several Assignee fields for one Issue. So for example a single issue has an editor, layouter, texted and so on. Of course this is possible by using the custom field for users. But I want every field treated like an assignee, so, that everyone that is involved in one issue also gets the notifications on changes and if I put in the search query assigned-to I want to get all of the tasks I'm involved. It works, if I search for single fields like "Korrektor": me, but not for assigned to.

 I'll include screenshots to show what I mean. 

Can I somehow fix this? 

Thanks in advance!

Cheers, 

Karina