Changing owner of notifications - role limits?

Hello!

What drives the drop-down menu in the "change owner" email list in notifications and subscriptions? My list comprises of me (only person with app edit permissions), and my system office's realm manager (I think that's what their role is anyway).

I need a middle-ground to change subscription ownership to my team members - including those who otherwise have full app access, just not app edit permissions - as well as a new role coming on board that will have more limited access, but will be crafting their own notifications.

Thanks!