Alas, no, that won't work. Once the first phone answers, the call disconnects on the other phones. You are expecting the phones to conference in everybody at once automatically? 'fraid not. The products that page to the phones don't even do that. They use a multicast stream and highly specific cisco APIs to make the phone go off hook with speaker and microphone mute to listen to the stream. Again, this is possible with Call Manager Express, but not with Call Manager by itself. Crazy, I know.
John Lever
Telecommunications
Richland School District Two