Add Hotkeys to Tabs / Subtabs

I know this may be more difficult than it sounds, given the way MremoteNG stitches together various windowing methods-- but could it be possible to add Hotkeys to the tabs? Especially the SUB-tabs. The outside tabs aren't that big a deal to switch. But being able to Hotkey between the inside tabs would be really nice.

Personally, I'd even be happy if it could be done between linux sessions, and then a group of putty windows would act a lot like "Konsole" (a linux terminal manager).