The group specification names a group, either a compound name of the form windowname.groupname or a windowname followed by a group defined by fields and enclosed in parentheses. For example, you can specify windowname.groupname or windowname(field-specs), where field-specs are as defined earlier for the WINDOW statement.
In the example, you used the following statement to display the window MAILLIST and the group ADDR:
display maillist.addr;