Possible to accept multiple parent values?

I'm wondering if it is possible to make the child field dependent based on a multi-value select parent field?
The entity_reference view mode allows for multiple values in the form of 1,2,3 or 1+2+3 which all work at view level, but do not work when I set my parent field to have a cardinality of more than 1.

I would like to have a multi select for choosing 1 or more Regions and then the child dependent field fill in from the multiple values.

Is this possible, or should I submit this as a feature request?