You need to change the [Access Mode] for the service you wish allow or restrict for users. You do this by going to the [Any Service, General] tab and clicking on the [Access Mode] button. Once this opens you simply need to change it from the default [All Accounts] to [Selected Accounts Only, Selected Domains Only, Etc.]. Once this is set you can then go to each user/domains [Options] tab and uncheck the box for that service to remove it for that account or domain.
Once this is done the specific domains or users will not be able to receive the service you just restricted.