Tboooe, yes you can!
On the D5 under setup: set RC > Enable
On the P3 under setup: iLink > PCM, XLR > DUAL
Word set to 100khz
Then you can use the remote's "INPUT " to toggle between the inputs on the D5.
A word of caution: I tried to use another iLink cable and it didn't quite work. You have to use a good quality(make sure its S400 compatible) iLink cable in order for the 2 units to handshake. Also with the units set to send the WORD data, it takes longer for the WORD to light up/lock on.