pppoe multiple dialout

I tried to: connect 2x different customers in one building with there own PPPoe account.. I have an incoming internet connection bridged on Lan1..

I want to dial a customer 1 with his own account connected to LAN 2, dialing out on lan1..

and customer 2 with his own account connected to LAN 3, dialing out on lan1..
So that both customers can be managed on usage with radius manager.

I am struggling to understand the marking of each customer with the mangle option ? or is there a simpler way ?

Please help with this if time is available.

regards.
Vikus