Configure PHP and SuExec PHP5/4 addhandler issue

[devGOD]

I'm trying to get PHP5 and PHP4 to play nice on a website space that requires both.
1. mainSite.com script needs php4 and is set to php via Addhandler (works fine)
2. sub.mainSite.com needs php5 (apparently i can't override the parent site Addhandler) but its loading php4 even though I have addhandler set for 4.

Both php4 and php5 work fine, the server is default to 5. Someone told me this "Yes you can only load one php module. When you want to set the Handler in .htaccess for different php versions you should run fastcgi with the different modules." so my question is how do I set it so that both PHP5 and PHP4 can run and be switched via the Addhandler (.htacces) while on the same site?

Currently my Configure PHP and SuExec is set too...
Default PHP Version : 5
PHP 5 Handler: dso
PHP 4 Handler: cgi
Apache suEXEC: on

I was told to switch PHP5 to FCGI what should I change PHP4 too and would this solve my problem?

[cPanelTristan]

Have you tried renaming the scripts that need PHP 5 to .php5 and then setting that as the handler to load PHP 5 for the subdomain?