To add the Unix owner and group criteria to the window for use in searches, use the Own/Grp toolbar item.

To limit a search to items based on their owner, select that owner from the popup menu of owner and use the Owner is/is not popup to specify whether the search should be limited to items with that owner or to items whose owner is not that owner.

To limit a search to items based on the group to which they belong, select that group from the popup menu of groups and use the Group is/is not popup to specify whether the search should be limited to items in that group or to items whose owner not in that group.