JES2 and JES3 use JES XCF for the same purpose - to communicate data among the JES XCF group members. To allow both MVS and all the JES XCF members to know about each other, you need to define the members to JES2 or JES3 in their respective initialization data sets.

In a JES2 environment, refer to: z/OS JES2 Initialization and Tuning Guide and z/OS JES2 Initialization and Tuning Reference for defining a JES2 MAS name and relating that MAS name to the group name defined on a JES XCF attach (IXZXIXAT).

In a JES3 environment, refer to: z/OS JES3 Initialization and Tuning Guide and z/OS JES3 Initialization and Tuning Reference for defining the JES3 complex name and for relating that complex name to the group name defined on a JES XCF attach (IXZXIXAT).