You can have multiple bindings using the same midi event, just create several mute or solo bindings, one for each loop you want to control, and use the same midi event. They will all get fired when that single midi event is received.
I think what you interpret as abrupt volume drop is just what a low feedback value does. Basically, it is a fixed gain attenuation that is applied to the signal going back into the loop so every time around the loop the level will be that much less than the iteration before. It is not a continuous "fade-out", you will hear the gain change at each loop iteration.... this is pretty standard delay feedback behavior.
