Jerry,
Are you talking about the BBS Hierarchical Addressing Protocol that is common with people running NOS BBS'es?
ftp://ftp.tapr.org/bbssig/recommendations/hierarchical
In all honesty from what I remember it's a lot of manual configuration, that really seems quaint to me since all the NOS programs also speak SMTP, the standard today.
It would seem the same could be accomplished using SMTP standards by setting up some mail aliases.
I'm going to recommend the TAPR NOS-BBS list for (Hierarchical forwarding) things of the non 21st century:
https://www.tapr.org/mailman/listinfo/nos-bbs
---- Quote ---- Is there anything written on the operation of amper.org mail forwarding? We routinely run h-address packet mail forwarding and I see some ampr.org mail bulletins coming in from all over the world. I’m interested in the addressing, routing, and just how does this mail forward. I run Ubuntu Linux JNOS latest version.
Jerry, N0MR