Remove exchange forwarding for some users and loop help

Hi

We need to remove the email forwarding settings for some of our users. Some users have their email forwarded to "My email [BLAH]" where "[BLAH]" always appears in the name of the contact that the main mailbox forwards to. 

The email address of the "[BLAH]" contact also includes "blah.com" in the external email field.

We need to remove the forwarding for any user who's forwarding settings points to a contact with "[BLAH]" in the name or blah.com in the contacts external email field.

Anyone know some Powershell that might help? I can do the disabling but I can't do the look to go through and check the exsting settings and only remove if ...

Any help much appreciated.

Olly