Two contact headers in register packet

Hi,

I am using asterisk where it registers one user xyz to myregister.com server. i was wondering, is it possible to send two contact headers in the register packet? for example like the following packet… and also can i set the q field?

REGISTER sip:myregister.com SIP/2.0
Contact: sip:xyz@192.168.0.10; q=1,
sip:xyz@192.168.0.11; q=0.7



Content-Length: 0

Thank you.