We have SPA504G and SPA525G phones, no side cars. We're looking to have the same extension on multiple phones. For example, we have an extension for Support and we want three phones to not only be able to answer when it rings (this I can do), but also see when there is a message on the extension. (this I cannot get to work). Can someone tell me the proper way to set this up with 3CX and SPA 500 phones?