The syntax for changing a table entry's group uses an indexed entry to identify the entry, as shown below (this syntax is fully described in NIS+ Syntax for Objects and Table Entries).
nischgrp new-group [column=value,...],tablename
new-group is the fully qualified name of the object's new group.
column is the name of the column whose value will identify the particular entry (row) whose group is to be changed.
value is the data value that identified the particular entry (row) whose group is to be changed.
tablename is the fully qualified name of the tables containing the entry whose group is to be changed.
... indicates that you can specify group changes for multiple entries.
Be sure to append the domain name to both the new group name and the table name.
The example below changes the group of an entry in the hosts table of the doc.com. domain to sales.doc.com. The entry is the one whose value in the host name column is virginia.
client% nischgrp sales.doc.com. '[name=virginia],hosts.org_dir.doc.com.'