Selection in pre-selection

Rhino Rhino for Windows
1

This might be an easy one, but I didn’t find out:
Can I have a pre-selection and then do another selection in this set?
Think of chaining different selections.

2

Hello - Shift-select adds to the current selection, Ctrl-Select removes from the current selection - is that what you mean?

-Pascal

3

Yes, I know.
But let’s say I want all green curves smaller than <len> on layer 16 and only in this set I just handpicked. What now?