AllowGroup [ group-expression]
1.1.1 and later
AllowGroup specifies a group-expression that is specifically permitted within the context of the <Limit> block it is applied to. group-expression has the same format as that used in DefaultRoot, in that it should contain a comma separated list of groups or "not" groups (by prefixing a group name with the `!' character) that are to be allowed access to the block. The expression is parsed as a boolean "and" list, meaning that ALL elements of the expression must evaluate to logically true in order for the explicit allow to apply.