Asterisk BLF on other PBX system


I was wondering if it is possible that Asterisk could check BLF status on other PBX system. The PBX system does not support subscribe and notify status on SIP, but Asterisk does.

Asterisk and other PBX are connected via H.323 channel, or SIP-T.

All I would need is that Asterisk sends his subscription and notify to another user and another ip.

For example:

Asterisk IP is, and other’s PBX ip is The issue is, can Asterisk send the subscribe and notify to