How can I unconditionally forward calls to Avaya IP OFFICE 500V2 (7.0(36))?

Question

SIP

I re-read a bunch of manuals, asked the technical support of Mango Telecom and Beeline, no one can help. There is a number 8495ххххххх, this is a 4-channel sip number, it comes to us in the Avaya IP OFFICE 500V2 (7.0 (36)) (ethernet) PBX and now the wiring goes to 2 Avaya telephones. I would like to make an unconditional forwarding from this number to the virtual PBX of Mango Telecom. In Mango Telecom they say that we have provided you with an address, then the issue should be resolved by Beeline. And Beeline says that we can only do unconditional forwarding to a phone number and not to an address ... Theoretically, IP Office should support forwarding to a sip address ...