Thank you again. Very kind of you. I’ll try this tomorrow.
In the IAC Driver. In Audio Midi Setup, Window => Show Midi Studio => double click on IAC Driver => hit "+" to add IAC Busses and relabel them. Pull your controller as the input in Midi Patchbay and use these as the outputs. Then, use these busses as the inputs in Logic. When you want to play outside the range on say the viola track either change the range in midi patchbay or switch the midi input in Logic.
Not sure I totally explained that correctly. If you hit a snag let me know. I have Logic also and can try it.