[Freeswitch-users] Refusing REFER requests

Is there any way to ask FS to refuse a REFER request? I mean, when a REFER is received, the first thing FS does is to disconnect the channel of the referrer. Then, it sends the other channel to the dialplan. But I want to prevent the unbridging of the call in some circumstances (meaning: some destinations for transfer are not valid). Obs: I don't want do disable support for REFER as I know it can be configured in the sofia profile. r, takeshi