Break Selected symbols off into new set of symbols

[George-Frazee]

If I have a set of instances of symbols, is there a way to select a couple of them and say "make this a new set of symbol." I don't want to detach or desync them.

I know I can detach one and then create a new symbol, but then I'd have to rearrange the new symbol to match where the old set was.

For a visual:

Here are 4 instances of the "Test" symbol in my document. What I'd like is some way to select the two in one of the artboards and say "these are a new symbol" somehow.

I don't see a way how but I figured I'd ask and if not make it a feature request.