Switching between manual and autonomous control

Hey people,

I was wondering if there is a possibility of switching the control of my drone from manual (through RC transmitter) and autonomous mode (thourgh software running on RPi+Navio). I would need something like a switch that would interrupt the intructions comming from RPi.

Can I somehow attach a channel command from the radio receiver to Navio, so that it would act like a on/off switch?

Thank you very much.