Multi-node BBS'

Gary's pulling up a BBS pushed me onto a wave of nostalgia so I've been digging through my old DOS archives of BBS software and the like that I picked up years ago and I came to a question. How did people set up multi-node BBS' back in the day? I know you could run something like Desqview and run multiple copies on a single system, and some BBS' (like TBBS) had built-in multitasking so it handled multiple modems. And, of course, you could get fancy and run a Novell network. Were there other ways of doing this? I also saw a random mention of multi-node Commodore BBS'. Given Commodores didn't network or multi-task, I'm curious if the author of the note was mistaken, or if such things existed -- and then how did they work? My thanks for helping with my flashback; - JP