here is how we get around the glaring miss by Cisco to implement a broadcast huntgroup in the CME system...
1) setup one dummy line each for however many simultaneous calls to the main dail-in number you want to be able to answer (i.e. if you want 6 phones to ring, but only expect a maximum of 3 simultaneous calls on the main number, then create 3 dummy lines -- less is better).
2) create a sequential hunt group pilot line as the main number inbound from the FXO and plar the FXO to this number
3) on each of the phones you want to ring, create an OVERLAY button line, overlaying all three dummy lines on the one phone line. If you want a single phone to be able to answer multiple calls to the main number, create a second, or third overlay button line.
Essentially, this is still a sequential hunt group, but since the lines on each phone are set to all three, as the hunt group goes through the sequence, all phones still ring for each sequential line.
Hope this helps.