You could use the UART in Mode 3 (9-bit) to do the addressing.

As to whether it's worth it, and what ccomplexity is justified - only you can answer that within the requirements & constraints of your project!

It's not hard to implement a simple protocol which uses a checksum & ACK.

All depends on how "unreliable" your "network" is, and how important it is that errors are detected (or how damaging it will be if they aren't!)