asterisk users - Apr 2004 - Call parking on central asterisk system

I have 2 asterisk systems connected with an iax2 trunk. The first has
SIP phones and x100 line cards, the second at a remote location has a
TDM with zap extensions. When calls are parked by the zap extensions at
the second system, the calls are parked on the second system so users at
the first server cannot access them. I will try to create an extn to
connect to the second system to collect the call but would prefer to
have the second system park the call at the first. 

Does anyone know how I can do this?

TIA

Stuart.