Limiting procedure visibility

Folks:

Anyone know if it's possible (in V5R1) to create a procedure with
limited visibility in a service program?

Basically, I want to create a procedure in a service program that is not
exported to other programs that bind that service program, but is
accessible to other modules that are in the same service program.

For instance: The service program consists of modules X & Y.  Procedures
A, B, and C, are in module X.  Procedure D in module Y wants to
reference procedure A, but I don't want any other programs to be able to
reference procedure A.

In Java I would define the method (procedure) as having 'package'
visibility ... so that other routines in the same package (service
program) can access the routine, but nobody else can.

Am I asking for the impossible here?

Thanks!

david