Stop decombining on too many windows

If this is technically possible it would be awesome to do.

I really like the "Decombine Active group" feature, in fact it's one of the main reasons I installed 7tt. But I have a small problem - when I'm doing research I tend to have 15+ books open, along with regular things like folders, browser windows and text editors. When I switch to the book group takes over the entire taskbar, causing everything else to barely even fit - just some 0-margin icons remain.

The idea is putting a limit on decombining - say at 15+ objects in the active group do not decombine.