Change host settings to accomadate several domains

We have the Pro hosting package with Brinkster.com. We also have multiple domains. [login to view URL] [login to view URL] [login to view URL] [login to view URL] [login to view URL] [login to view URL] [login to view URL] At the present time we have several of the domains pointing to our main website which is gbtpos.com. The domains being redirected to [login to view URL] are [login to view URL] [login to view URL] [login to view URL] [login to view URL] [login to view URL] is being hosted by another company ([login to view URL]). We are currently working on websites for [login to view URL] [login to view URL] [login to view URL] We can't seem to load the websites correctly. We uploaded the files for [login to view URL] but we get a "server not found" message. At the moment we are working on sites for [login to view URL] [login to view URL] so we want to continue to redirect them to [login to view URL], but as soon as we load the website we need someway of directing it to its own website. We have a script that someone wrote for us, but I don't understand it.