Running PHP 4 & PHP 5 Simultaneously

Greetings! I was wondering if it is possible to run both PHP 4 and PHP 5 simultaneously under Apache 2.0.43 on Windows XP Home. I currently have PHP 4.3.0 (SAPI) running successfully under it, but would like to add PHP 5-dev for experimenting. What I'd like to do is allow PHP 4 files to have a *.php while PHP 5 files have a *.php5 extension. The problems I'm running into are: First, both versions of PHP identify themselves as 'php4_module'. Thus Apache gets confused and won't startup when I try to add the second (PHP 5) module. Secondly, how do I work having two 'php.ini' files running around. I can't very well put them both in 'C:\WINDOWS' and there doesn't seem to be a way to place them both in '*\php\sapi' like php4ts.dll. Hopefully this all makes sense. Jason