Howto: Special outgoing trunk routing


I need to set up (sip) routing based on the extension. I have 3 SIP trunks which work pretty well, however I need to route two extensions to the same SIP trunk each time (for accounting/lcr purposes).

That is:

-) All extensions (except 2) dial out via the normal outbound routing method.
-) 2 extensions always dial out via another SIP trunk.

Is this possibile? I guess I have to use custom contexts but some hints will be really appreciated.

Thank you.