Program binds to Serviceprogram in an fixed library instead of searching the LibraryList.

Dear all,
 
We create systems that can interact with many banking systems.
To do so we make use of API programs to retrieve different types of data or 
inflict execution of bankingssystem functions.
Typically we have in several API library's the same named API programs that 
execute the same kind of functions to different bankingsystems.
To interchange the API used by the basing system we just change the API library 
used.
 
To modernize one and other we have planned to create one serviceprogram as API 
for each bankingsystem containing all the to be used functions to the 
bankingsystem.
However when we create programs in the basingsystem and define the 
serviceprogram to be used it not only stores the program but also the library 
where the first occurrence of the serviceprogram is found.
 
At execution time not the library list is used to find the serviceprogram and 
execute the correct one in the in the library list defined API library for its 
environment but the one that was administrated when the program was created.
Obviously this does not give the correct results and at clclient sitesith other 
lilibrary structurest would even create disasters.
 
Is there a way to make the system just search the library list and execute the 
service program that is first found in the library list? As it should do! Or do 
we have to refrain from this and need to keep on using the existing Call's??
 
Kind regards,
Eduard Sluis.