I am trying to query active directory and I know that I can do a search like this:

(&(objectClass=user) (&(mDBStorageQuota=10000)))

where it searches for all objects that are 'user' objects and have an exchange lower limit set to '10000' which is 10MB. What I am trying to do is a search on a field that is not equal to but contains a string:

(&(objectClass=user) (&(proxyAddresses=*@mydomain.com)))

Where it searches for all objects that are 'user' objects AND have an SMTP email address that contains '@mydomain.com' in the end of the address. Our company has 4 affiliates so each user could possibly have 5 or 6 email addresses that will all resolve to their email inbox. One of our divisions merged with the main affiliate and we are trying to search all accounts for email addresses that contain that division's email address. Anyone have any idea how to word the search string so that it is not an '=' but a 'contains' search string?