Tab Groups can be saved/configured as destructive (replace current tabs) or add to current tabs. There is currently no way to change a Tab Group's open action on the fly. The Tab Group's definition has to be edited and changed. I'd like to propose the addition of modifier support. In its simplest form it could be...
Click = open tab group as currently configured - either destructive or additive
Shift-Click = reverse the configured action - so destructive becomes additive and vice versa
Another approach would be to allow the user to configure generic Open Tab Group modifiers with options like Reverse Configured, Force Destructive, Force Additive, Open in New.