Yeah for sure you can do it like that too.

OR, the master PIC will use 3 serial PINs interruptable (let's interrupt on PORTB change) Once he got interrupt on:

1. PORTB.0, do serial IN for PIC1
2. PORTB.1, do serial IN for PIC2
3. PORTB.2, do serial IN for PIC3

Let me know wich PIC you'll use, i'll try to figure out something. Tell me a bit more about hardware (display, eeprom blah blah blah) Maybe we can use one master PIC that have enough of INternal EEPROM space.