Way to register "Surrogate PBX" with triggered registration based on SIP OPTIONS respose?

Hi,

I have PBX which does not send OPTIONS, only replies to my OPTIONS with 200OK.

I have configured Surrogate-agent with "register-mode = triggered", which NEEDS SIP OPTIONS to be sent by PBX in order for SBC to initiate REGISTER for this PBX.

Is there a way to trigger registration only based on 200OK response?

I know there is "Automatic" register mode which would register PBX no matter what (PBX does not have to send anything or reply to anything), but I cannot use this, because I have 2 georedundant SBCs and having same surrogate agent with Automatic registration would send 2 registrations to IMS from 2 sites for SAME number.