Missing user related objects checkmark - How to solve?

[Nicole Brückner]

Dear Community, 

We face the issue, that we have a legacy asset custom field within our instance, where the possibility was given, to checkmark the option "Restrict to user related objects": 

Within the new object picker fields (not the referenced ones). I tried to reach this with the following: 

This is working on the first level, buuuuuut: All referencing fields are now not working anymore: 

With the restriction above

Without the restriction above

Any ideas how I can achieve a workaround due to the missing "User related object" checkmark?

Best regards-

Nicole