Help designing an access policy to work across multiple subdomains in Sharepoint?

I have a working access policy that works great for a pool of Sharepoint servers. My problem is when the user authenticates using username and password to dept1.mine.com they are prompted again when they click a link that goes to dept2.mine.com or dept3.mine.com. All of these sites reside on the same Sharepoint server(s). All of these sites are accessed through one virtual server and one pool of servers. Is there a way to have all the sites accessible after a single login?

Logon Page -- AD Auth -- SSO Credential Mapping -- Allow