asterisk users - Jan 2007 - Create a group of SIP acoount for outgoing calls ?

Hi

actually, for call i use ZAP Channels on a E1 and SIP Account on a VoIP 
provider ...

in Zap, we use group and we have:
        exten => _1XXXX.,2,Dial(Zap/r1/${EXTEN:1},50,rt)
        exten => _1XXXX.,3,Hangup
r1= he change of channels at all calls channel group 1


It's possible to create a group of SIP Account and use same "r1"
for outgoing calls ?
r2= he don't use the same account into sip group 2

Thanks bye