[Zope] Set Up Zope Webhosting

Our company developed sites for our clients using Zope. We placed them on our server. Now every user has to start his own Zope by running 'start' script. So there are many Zope processes running in our server now. Luckily, there are still not many clients :). But I think that is a bad way for running Zope webhosting. So, is there anyone here could tutor or show me how to set up Zope Webhosting better? Thanks. -mico-