Load Sharing Error

I got 2 ISP, 1 is use PPPoE and 1 is use IP Base. and i successful created load sharing and it work 1 1 isp is fail over.

But the problem is i use NAT for my Telephony System (Elastix) to my branch in other province that can access through my public ip in PPPoE it sometime Using WAN2 Connection from isp2 that don’t have public ip. so it my branch connot connect to my phone server using ip phone.

I try to force my Local IP of Telephone server only use PPPoE connection only but it don’t work even thought i use Mangle or Route Rule.

Any Idea?

Sorry for my english.

Thanks