The following note discusses how privileges are granted to a user listed in more than one group in an ACL. This information should be considered as part of the topic "Acceptable names in the ACL" under the subheading "Names of groups" in Managing Domino Databases.
NOTE: If a user is a member of more than one group listed in the ACL, but not explicitly listed in the ACL, the user will have the highest level of access granted by any of the groups. The user will also have any additional privileges granted to any group in which they are a member -- for example, additional roles and any other selected privileges. However, if the user is explicitly listed in the ACL the access level, privileges, and roles granted to the individual take precedence over any privileges assigned to the group(s) in which that user is a member; group privileges are ignored for that user.