using net.data and webfacing together

Does anyone have an idea how to handle the following:

Several different net.data macros ask the user to enter a customer number 
as input for various inquiries (all items bought by a customer, all sales 
reps who handle a customer, all invoices sent to a customer, etc.)  We 
have a pretty good customer search program written in RPG which has been 
webfaced.  We'd like to have the different net.data macros "call" the 
webfaced customer search, have the user click on the desired customer, 
then have the customer number "returned" to the net.data macro.

 I'm thinking that the net.data macro could include "?calling 
program=MACRO1" as part of the URL that calls the webfaced search, and 
then have the RPG program somehow interrogate this to find the name of the 
net.data macro that called it.  (Is this in an environment variable, and 
can i get that from a webfaced program?)  If that is possible, then adding 
a HREF in the webfaced program that goes back to the appropriate net.data 
macro should be fairly easy.

Larry Kleinman
Kleinman Associates, Inc.
212-949-6469
203-255-4100