Exclude new AD accounts from activating PCNS

We are using FIM 2010 R2 to provision accounts to two different Active Directory domains.  We use codeless provisioning.

Users may start with an account in domain A or B only, and later on they get an account in the other AD domain.

So if a user is created in domain A first and later on they are provisioned to B, PCNS is picking up the initial password for the newly created domain B account and then users are getting their existing passwords overwritten if they have other accounts linked in FIM.

Besides adding sync rules to add a new account to a group recognized by PCNS for exclusion, is there another solution to prevent newly created AD accounts from triggering password changes?

Thanks.