Apache Reference: mod_auth, AuthGroupFile
Textual File of Authentication Groups
Syntax: AuthGroupFile A
Example: AuthGroupFile etc/groups
Since: Apache 1.0
This directive sets the name of a textual file containing the
list of user groups for user authentication. The argument
filename consists of the path to the group file. If not
an absolute path name, it is treated as being relative to the
ServerRoot. Each line of the group file contains a group name
followed by a colon, followed by the member user names separated
by spaces (for example, ``foo: bar quux'').