In it's simplest form, connect ONE wire between the comms pin of your choice on ALL your PICs. The Master has a LOW VALUE Resistor (say between 1K and 4K7) between it's comms pin and Vdd. All pics idle in RECEIVE (Input) mode.

MASTER sends a Transmit Request to the SLAVE of it's choice. The SLAVE will then reply accordingly. All PICs on completing communication return to idle in RECEIVE. No problems here. SLAVE addresses can be individually coded into the SLAVE software, or, more commonly, assign some pins on the PIC (in your case for ten SLAVES you will need four pins) to designate your SLAVE address. The SLAVE will read those pins at power-on and assign its own address accordingly - this approach is more sensible as then you only have to write ONE piece of code that will fit all the SLAVES.

If the SLAVE PICs are remotely located (ie in other parts of the building or in external equipment), then you will need a more sophisticated interface, as 0-5v one-wire lines will have a transmission limit. Try LOW baud rates (eg 300-1200 baud) at first. The upper limit will be determined by the pull-up Resistor and the number of PICs loading the comms line.