Ok, now I have a little problem!
I have tested the system with three tx and ten rx, and it works! but now I have five tx(16f648a) and ten rx(16f648a) on the same serial line. Each transmitter have a 1k resistor on the tx pin. I use serout2 and serin2 command. Now I think I have a signal problem because any rx doesn't receive the signal! I check it with a scope and I can see that for every tx that I add to the system the signal go down of little.
How can I do for make all work? Help me please!

thanks in advance!