provided by Star2Billing S.L.

Have 1.9 installed.

Have 2 different plans.

[a2billing]
exten => _X.,1,Answer
exten => _X.,n,Wait(1)
exten => _X.,n,AGI(a2billing.php,1)
exten => _X.,n,Hangup

[a2billing2]
exten => _X.,1,Answer
exten => _X.,n,Wait(1)
exten => _X.,n,AGI(a2billing.php,2)
exten => _X.,n,Hangup

In Admin console created second config with settings I needed.
Incoming routes pointed to different Custom Destinations:

a2billing,${EXTEN},1
a2billing2,${EXTEN},1

When I make test call I can see in logs next:
-- Executing [DID@from-trunk:5] Goto("SIP/TRUNKNAME-0000002e", "a2billing2,DID,1") in new stack
-- Executing [DID@a2billing2:3] AGI("SIP/TRUNKNAME-0000002e", "a2billing.php,2") in new stack

But it's using settings from agi-conf1.