"I think that even in the case of an external, it's difficult to know whether there's a signal connected to a signal inlet, or not (...) I think Eric Lyon's externals do what you want"I guess it can be tricky, but not impossible. I'd be really surprised and blown away if it turned out to be impossible.
And I guess it is actually impossible to work this out in a patch, huh? I wouldn't be surprised...
thanks