Include/Exclude Powerlist in New Powerlist Setup

It would be great if there was a way to include or exclude an existing powerlist when creating a new powerlist. I'm finding that for certain communication types, we're essentially building powerlists that are combinations of existing ones or that seek to use a set of criteria (minus people in a specific powerlist to avoid duplicates).

For example, we have one communication that needs to go to all Enterprise clients if they are a certain role PLUS all Agency clients independent of role. Generally those groups are treated differently for all other types of communication but for this specific comm, we need to include both groups. 

Having this include/exclude powerlist logic would help us scale and ensure parents groups are properly updated if we need to update a child powerlist. 
Not as straightforward as it sounds when you consider the fields that are added to each of the powerlist. You could have a field in Powerlist 1 that is not available in the other Powerlist 2 because each of them can be from two different object and not necessarily Salesforce contact object. 

Will wait to see if other users too feel the same way!