Exchange 2010 with Domain Name which also hosted on Google

Hi All

I need your help to configure my Exchange 2010 Server.I configure my Exchange server with domain name which already hosted on google apps for mails.So I have few users in my exchange 2010 server and few in my google apps account.Problem is when my users from exchange send mail to users which are on google apps ,it bounce with error #550 5.1.1 RESOLVER.ADR.RecipNotFound; not found ##

Any help will be appriciated

Thanks

Vijay