Underneath the Groups key is a list of user groups who have entries in the policy file. Since a user may belong to many groups and those groups may have conflicting settings, it is important to specify an order in which groups are processed. This order is contained in the GroupData\Priority key, which has values in the form "1"="group name", "2"="group name", and so on. "1" is highest priority, and the priority diminishes as the number in the value name increases. The downloader reads the group priority values and then processes groups from lowest priority to highest; that is, the downloader begins with the highest numbered value and works to the value "1".
For each group in the priority list, the downloader determines if the user is a member of the group. If the user is in the group, the downloader should try to find a key with the group name under the Groups key. If such a key exists, the downloader merges the registry image under that key into the HKEY_CURRENT_USER key. It is not an error if a group is specified in the priority list but does not have an entry under the Groups key; it simply means that nothing happens. This process is repeated for each group in the priority list. (If a group has an entry under the Groups key but does not have an entry in the priority list, it is never processed.)