I'd like to set up a one-touch button to access the Voicemail from any extension with the option to check either 1 of 2 voicemail boxes on the system. We're running a KX-TDA50/TVA50 system. "Intercom -500" works on some extensions and on some it doesn't. I made sure all extensions had a mailbox associated with it even though we're only using two VM boxes. Any insight would be greatly appreciated.