many ways to do this, and your choice of method depends on the speeds involved, on how you are generating RC0 & RC1 sequences, on your timing accuracy requirements, etc etc.
The simplist method of course is to continously read (input) the RA0 pin, and set a flag/ enable RC0 &RC1 if its High, and reset the flag/ disable RC0RC1 if its Low. Do this in a loop forever.
You could also setup RA0 to trigger an interrupt on positive edge, and the change the interrupt to trigger on negative edge. Basically change the sense of the trigger input on every input. I don't know if your PIC has this feature though. Set flags or directly enable/ disable your rc0RC1 within the ISR itself.
Many variants to these basic schemes, but hope this sets you on the right track.
cheers!