How to get all contacts base on a given email address

Hi,

I'm using functin contact_RetrieveByEmailAddress(username, password, siteId, emailAddress) of CatalystCRMWebservice to get a contact base on email address. When It has multi contacts match to an email address, webservice only returns one contact for given email address.

Please give me any way in order to I can get all contacts match to an given email address?