Polycom VVX310 connect with two freepbx servers / accounts

Hello All

I have Polycom VVX310 phone needing to connect with two different freepbx servers in same time like Line 1 and 2 server1 Line 3 and 4 server2
Each server has different sip extension number and password

tried with config file and pumkin server no luck. looks like im doing something wrong.

can any one guide on this