Peer to Peer Network in Vista

I'm looking for ideas on sharing folders in a peer to peer network when we go
to Vista. My company is an accounting firm, we are on a domain but my users
go out to clients and share client files by creating a peer to peer network.
We are currently using XP with a local account that each user logs on with
when they want to connect to the shared folder when out in the field. This is
a work around so there is no authenticating when browsing for the folder. I'm
tasked with finding another way when we switch to Vista Enterprise. I'm
finding that with the machines on the domain, I don't have a password option
to protect a folder. I'm also finding out I don't think there is anyway
around not having a local account again. This is my challenge. Is there
anyway around not having a local account on each pc again. If domain groups
would cache locally when off the domain this would work great. I also want to
stay away from a 3rd party util if possible. Your ideas would be appreciated.
--
Brian Snyder
Team Lead Support
MCP

It would behoove you, and save you much grief, to hire a network consultant.
Logmein, Gotomypc etc may be better options for off site users to access
specific files than what you are doing now.