CADWorxP&ID tab: Utilities > Add to Group 
Utilities toolbar: Add to Group
P&ID menu: Accessory > Add to Group
Command line: GROUPADD
Adds one or more component symbols to an existing group created using Make Group 
. When an external database is used, the added symbol is appended to the existing
row in the table for the group.
Avoid adding objects to a component type already existing in the database, such as
to an existing vessel type. Instead, create a new group using Make Group .