Handling multiple companies/library lists with Apache

Greetings all--what's the right approach for handling multiple companies'
web access coming through Apache in a single partition?

We're running a quote application for multiple companies using Apache in a
single partition. The web page calls a library-qualified stored procedure
which in turn calls a service program which in turn jockeys the library
list. The service program calls an ILE RPG program to do the actual
calculations and the ILE RPG program sets LR on before exiting.

The problem is that Apache keeps a soft lock on the files opened in the ILE
RPG program even though we do an LR='1' close.

Scenario:
* We handle a request from company A and everything is fine.
* When a request comes in from another company, and even after changing the
library list, *sometimes* the ILE program for company B looks at the opened
files (belonging to company A) without regard for the library name and the
application fails.
*If I reset the HTTP server, the same transaction for company B works
correctly. I've confirmed the weird behavior by looking at DSPJOB dumps
triggered by an error condition and I can see open files for company A in a
request for company B.

One potential solution is to add OVRDBF's to each company's service
program...yuk. Another is to hard-code the library name in the file
description specs and open each file...yuk. Another solution is to pass
the library name in through an input parameter...yuk.

Question 1: using HTTPD.conf, shouldn't we be able to control which IP
address goes to a specific pool of Apache instances? Web traffic from
company A's IP address would be handled by a company A server instance and
company B's traffic would be handled by a company B server instance. This
seems like the obvious solution but the web people have not investigated
this option.

Question 2: is there another configuration option to handle this?

Question 3: is there some other way to handle this?

Thanks,
Xavier