Send Voice mail to numbers which are automatically disconnected in Ring group

I am using Ring group to place call on two number at same time but i want to send voice mail to that number which are automatically disconnected when any number has been received .

Is there any way to implement same functionality? please suggest.

Asterisk doesn’t have ring groups! That suggests you are operating under the constraints imposed by something like FreePBX. You need to ask people who know those constraints.

Also Asterisk doesn’t ring numbers, it rings devices. When Asterisk rings multiple devices, there is no requirement that they have extension numbers that allow them to be called individually.

I don’t understand what you mean by "when any number has been received.

Is what you want that the call be answered as voicemail, and two devices rung in parallel with that. If one answers, the call is redirected to it?

I doubt that can be done in FreePBX. I can think of an approach in pure Asterisk, but it is not for the squeamish.