Use 3way calling to do a sudo transfer

using asterisk@home
do you think its possible to use a x100p pots line to basically click over (flash), dial a phone #, and click back (flash)?
This could be used as a basic form of call transfer without using a SIP gateway.
The only negtive I see is that the incoming POTS line is basically busy durrung this time.

Is something like this possible, and if so, how would one go about implementing this…

So basically the person calling in on pots line, could be transfered to another phone, like a cell #… if not available to pickup a sip line, and the caller doesnt want to leave voicemail.