PushtoTest allows developers to create unit and functional scripts for websites and is an OpenSource Java testing tool. PushtoTest executes scripts written in a number of scripting langauges using the JVM so it uses the same technologies as Hyperic.
Creating a PushtoTest plugin would allows website functional test scripts to execute like any other Hyperic test. Perhaps this should be structured in a way that the PushtoTest scripts can be executed on a 2nd machine to allow for many scripts to run against many websites without impact to the Hyperic environment.
I am not familiar with PushtoTest, but you could probably write a Script plugin for Hyperic. You will need this plugin and a wrapper script for PushtoTest. Can you run PushtoTest scripts from command line ? If so it should be not a problem to integrate PushtoTest from Hyperic HQ. More Infos about Script Plugins: http://support.hyperic.com/display/DOC/Script+Plugin