Set up a route on the PACS server setting the traffic to network 192.168.203.0 go thru 192.168.200.254
On Windows it should be like this:
route -p add 192.168.203.0 mask 255.255.255.0 192.168.200.254
Linux:
# /sbin/route add -net 192.168.203.0 netmask 255.255.255.0 gw 192.168.200.254
Hope it will work. Cheers!