How to make Zap/3 detect call forwarding at phone company?

I have a TDM4xx card connected to two Verizon phone lines. All works well except for when I call forward (via Verizon) a Zap line. Verizon gives a little half ring as it forwards the call. I can not get the Zap to ignore that. I tried putting a Wait(6) at the top and it will wait, but then answer the line, long after the call has moved on. How do I get the Zap channel to only answer if it sees 2 or more rings??

If the half-ring is somewhat consistent, then you might be able to use distinctive ring features in zapata.conf to send such calls to a separate context that simply hangs up the phone.