[plug] e-mail address problem

[Jon L. Miller]

Got a location where there are 2 domains DomA and DomB.  They are
connected by a dial-up connection.  All users are created at the main
domain DomA.  E-mail addresses are supposed to be johndoe at doma.com and
janedoe at domb.com But for some reason janedoe e-mail came up as
janedoe at domb.doma.com  and this is incorrect. Does anyone know how to
fix this so janedoes e-mail coming to DomA is given the correct address
of janedoe at domb.com?

The mail system is Postfix.

TIA