Ok so I know back in chan_sip if I had a phone with multiple lines I had to basically put something like, for the main line, register line 2. For instance if 302 was the main line and 303 was line 2 on the same device my chan_sip config would look something like this:
Note on 302 it has “register=303”
What is the PJSIP equivalent to this?
 type=friend host=dynamic defaultuser=302 secret=xxx context=internal-home dtmfmode=rfc2833 canreinvite=no callerid=302 insecure=port,invite mailbox=302@internal transport=tcp force_rport=no register=303 busylevel=4 call-limit=5 encryption_taglen=32
 type=friend host=dynamic defaultuser=303 secret=xxx context=internal-work dtmfmode=rfc2833 canreinvite=no callerid=303 insecure=port,invite transport=tcp mailbox=303@internal force_rport=no busylevel=4 call-limit=5 encryption_taglen=32