asterisk users - Jan 2005 - disable ringback of held call on zap channel

One Zap FXS channel has dialed to another.  Zapata.conf has transfer = yes
and threewaycalling = yes.  I flash on one of the phones, the other gets the
music on hold.  If I hang up the flashed phone, it rings back and I am
reconnected to the other phone.

Is there some way (with flash, not with #) that I could leave the other
phone on hold for a longer time?  Preferably without having to dial
something after the flash.

thanks