Aastra 57i line using different trunks

Hello experts,

I am trying to assign trunk 1 to line 1 & 2 and trunk 2 to line 3 & 4

trunk 1 = phone number 1
trunk 2 = phone number 2 so that work in both ways for outgoing and incoming calls.

Please advice how to approach. Thank You.

At least for outgoing calls