reading ppm/PWM signal into pic chip

[chevy6600]

Hi guys, i wonder if you could direct me in the right direction, what i want to do is to input 3 PWM signal`s, as per radio control, into pic chip and read the length of the pulse to get a spread of `250 ish` then do my algorithms then output the resultant PWM`s back out to 3 servos. Taking account that i have setup a 18F2620 to produce PWM to servo`s, but it has used 2 clocks.
a few axamples i can think of,
Q. do i convert the PWM input to analogue and feed this to the 18F2620 (what would be the best way?).
Q. Can i use the existing 18F2620 PWM `controller` program and have enough resources to do it?.
Q. would it best to add another pic chip and output the result to the 18F2620 PWM `controller to do the PWM output side?.
Note that the existing PWM `controller` program is still needed as it is, with it`s analogue inputs. So the entire system hopefully would consist of 2 analogue sensors outputting to 2 servo`s, and an PWM signal
from 3 control channels being interrogated and the result output to another 3 servo`s.

So in your wisdom, what would you think the best method of attack would be in accomplishing my goal ?.
Thanks for any input you can give.