Multiple different object select

An object should be able to be linked to other objects using a property without limit. Currently we can only link object A → B. If I want to link A to B & C, I'd be forced to use a text field, giving up on search and easy "quick create" functionalities.

Example:

I use a tiered hierarchical system with multiple levels. A source in my system should be able to be linked to either 1, 2 or 3, or multiple. Currently that is impossible.