b19rro,
I don't think this is what you are wanting, but as far as I know there is not a Camp-Ons Allowed or Receive Busy Instead of Camp-On function for IC Calls.
There is a Camp-On Indications Flag that will the tone and display signal when a user has camped on, but it doesn't stop the person from Camping-On or provide them with a Busy Signal. Of course you could pay for a File Based MoH License and then record a Busy Signal and play that for Calls that have camped on to the device, but it will do that for all calls camped on to that device.
What you could do is setup a System Forwarding Path that routes IC Calls on a Busy condition to the users Voice Mail or just hang up on them; I think the VM option is better. You could also record a busy signal on a CRA prior to it hangin up on them; that is as close to the scenario that I can come up with.
Of course I am not the most proficient when it comes to using the phones so there may be another way; especially if they have an Executive Style phone then they can send the calls where they want them to go by pressing a button.
Thanks,
TE
