How XCF Works Together with the Group User Routine

XCF works together with the group user routine in the following manner:

XCF schedules the group user routines of active members of the group when specific events occur (such as a member changing state or a missing status update). For an event that affects multiple members, XCF provides a separate notification regarding each affected member.
XCF passes information to the group user routine through a parameter list (mapped by the IXCYGEPL mapping macro and pointed to by GPR 1).
The group user routine takes action based on the information in the parameter list.