@zeke-holloman communications – peer2peer – is a deep subject.
Many years ago I wrote the code for a comms stack to use the 9bit UART to poll an array of processors. In the end it was 2people for 18months to get it working reliably. So its not trivial, but i had a fantastic time with it.
It may that you have a special case and only want to use 8bit communications, it partly depends on what you want to communicate.