Yes UserGroupID.... you can't pass multiple values with an '=' comparison... you need to use IN if you want to pass more than one value comma separated.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.