Would love this request:
I already raised one for Relation Scope:
https://community.anytype.io/t/-/1553
Where a type can only show relations which belongs to it
What you suggested is something similar to relations, where an object relation can only show types suitable to the relation 
Having the both of them is really important and should bring a lot more flexibility to Anytype. I’d link your request in mine to let people know there’s a similar request but for Relations