You'll have a hard time making it come in on different CM trunk groups. Yes, domain based routing is one of the keys, but making AAEP send calls to those different domains is another.
By default, AAEP works with a single 'zone'. Thing of a zone as a trunk config. So, you can have many zones with many domains and that's one way of assigning a number of channels to sales.customer.com vs service.customer.com BUT your apps dial out the 'default' zone unless explicitly developed to use the zones you've defined. If they ain't there today, odds are you're not getting your AAEP apps tweaked.
That defines how AAEP makes a call. How are you transferring? If it's consultative, AAEP makes the 2nd call and waits to bridge it, so AAEP is placing the call. If it's a blind transfer, it's be a SIP refer and telling the first thing - like the SBC - to redirect the call.
If you're using SIP refer with an SBC, you could probably do some magic there triggering on the destination number to make it hit SM for one domain vs another and in turn get the separation you're looking for on CM.