If you open up source control explorer and right click on the file/folder you can edit the security permissions on the file and control who can read or edit the file. Note that if a user does not have permissions to read the file then they will not even see that it exists.
If you do this then you probably do not want to include the release.web.config as part of your solution/project as the Solution Explorer would then show it as missing for the people that didn't have access.
Note that because of the fact the file disappears when you do not have read permissions, there are a few caveats about the dialog. It is quite easy to remove permissions for everyone to read this file (including yourself) which leaves you a bit stuck if you wanted to give yourself permission again as you wouldn't be able to see the file to set the permissions back again (see http://www.woodwardweb.com/vsts/dont_do_that.html).
If playing with the security settings you accidentally remove access from yourself to see the file, the way around this is to log on to the TFS server as an account that has local administrator rights and TFS Adminitrator rights (tfssetup user) and then you'll be able to see the file to change the permissions back again.