Setup voicemail only for external incoming calls

I’m looking for a way to have active voicemail boxes only if the call comes from the outside, and inactive for calls between extension (if the call is between extension the phone should continue to ring).
Does anybody have any idea how to do it?
I appreciate any idea.
Thank you

This is sort of a hack, but set your ring time in the General settings to a big number. Then have your incoming calls go to a ring group and set the time to voicemail to about 20 seconds.

Maybe that’s a sort of a hack, but you are a genius!

The problem remain only on calls from external that have selected directly the extension in the IVR, but it’s a minor problem.
Thank you!!

the offered solution has a charme but is not right for me. i look for solution like this:

calls from external:

  • extension busy -> signaling busy to the caller
  • extension no answer -> after x secounds go to other destination (announcment and reroute the operator)
  • extension unreachable -> go directly to other destination

calls from internal:

  • extension busy -> signaling busy to the caller
  • extension no answer -> ring unlimit time (or a long time)
  • extension unreachable -> “Destination not available” or something like this standard message

I´ve looked for a solution but can´t find anything like this. At this time all incoming call go to an ringroup and than to extension. On this way i can have redirection only for externals calls. But in combination with voicemail this solution no longer works.

Has anyone an idea? I don´t know enougt abount contexts so i can´t look for a solution based on that.

Thank you for your help.