By explicitly assigning an XCF group to a transport class, you give the group priority access to the signaling resources (signaling paths and message buffer space) of the transport class. All groups assigned to a transport class have equal access to the signaling resources of that class.

Assign one or more XCF groups to a transport class using the GROUP keyword of the CLASSDEF statement or, after IPL, using the SETXCF START,CLASSDEF command or the SETXCF MODIFY,CLASSDEF command.