Don't know about hotkeys, but:
You can do exactly that plus other cool things with the advanced remote, if that's an investment you'd be willing to do.
I wouldn't want to live without the remote again.

Sorry for beeing unclear on this one: indeed Totalmix FX was meant (with MADIface USB). If you are on a light setup with a very small screen (eeePC!) it is too difficult to manually switch programs all the time (even with hotkeys on this small screen; then pushing a hotkey and afterwards again, then toggling back to the recording program.) Don't want to buy ARC, rarely any need otherwise. It seems indeed possible for a program checking/cntrolling a key even if not in the foreground, Samplitude can do this with the stop-key.

(My signature is a bit outdated - but great that those old card works without any hassles for many years already!)

It's not only "about an eeePC" (which is btw. for multitrack recording only absolutely sufficient, 16 tr. at 48k no problem!) . If you include a talkback (and listenback, really helpful) function it would be most helpful to adapt it to the highest possible degree to real world situations, where you have a recording program, TM and a hotkey for talkback. But that's not enough if you have to do complicated switching back and forth between the programs every time and inconvenient toggling instead of a momentary option.
I'm sure with Autohotkey it can be done also, but have to look into this if I have time.