[Freeswitch-users] Need to intercept Transfer from phone

I want to intercept a transfer originating with a button press from the phone. What I can locate about VOIP, still learning, is that this should be a REFER request. OK, so in the middle of an extension, can I monitor for this, or is this more of needing to monitor for this EVENT? I only want transfers to go to an IVR if the line is busy and present some options (i.e. continue holding, voicemail, ect...). I thought campon would work, but not quit what I need. Just point me in a direction, I am learning as I go! Thanks, James