Moving from Exchange to something

I'm contemplating shutting down my Exchange operation; a single Exchange server in a medium size church, with five full time staff members.  There is a really large Contact list, but it is not used for mass emailings because of our slow internet onnectionk (DSL). Constant Contact us used for that.  One alternative I'm pondering is just using Gmail.  Each staffer would have his or her own address in the form of Individual-Identifier.Organization@gmail.com, e.g. ronh.ChurchName@gmail.com.   There could also be, I think, a general purpose / multiuser address, e.g. office.churchname@gmail.com to which each staff person would have access.  Each person would/could have his or her own contact list, sort of like some do already in their Outlook clients.  A contact list could be maintained in the multiuse account, somewhat simulating the Global Account List in Exchange.

I'm hoping that the community will point out any flaws in this approach and make suggestions.

It is increasingly seeming to me that running an Exchange server in this environment it like using a diesel locomotive to crack walnuts, especially with the existence now of such services as Gmail which wasn't an option 18 years ago when we adopted Exchange.

I'm already using Google Groups for a closed group that 20 church leaders use to send messages among themselves and no others.

Any and all thoughts much appreciated.

ron hicks