Just in case you have it inside out....telnet 'through it' wasn't real clear to me.
If you have a BBS running on a PC. The PC is connected to two networks say, the packet RF network and the 'internet' IP network.
You can telnet over the internet to the BBS if you have that configured...you'll see the BBS prompt just as you would over packet generally.
Via RF you can get in via packet network to the BBS.
Now, some nodes, you can get in to the node via RF and packet, once in the node they have a telnet interface that will allow you to telnet from that point...over the internet generally so it looks like you -> radio -> tnc -> RF -> BBS -> telnet -> internet/IP network -> telnet destination.
Now there are more convoluted IP tunneling over ax.25/packet situations that can muddy this up, but do any of these cover what you want to do?