Using a 1815dn in a multi-LAN environment (dual NIC PCs)

I’m having trouble getting an Ethernet connected Dell 1815dn multi-function printer working to my satisfaction in a multi-LAN environment. The printer is attached to a 100MB LAN with a number of PCs that are all running XP Pro SP2. Two of the PCs have two NICs each. One NIC in each PC is connected to the same network as the printer (192.168.1.x) and the other NIC is connected to a different 1GB network (192.168.0.x). The 1GB network is used to transfer very large video files between these two PCs. The two networks are not bridged or interconnected in any way.

When the dual NIC PCs are configured so that the 100MB network connection is accessed first (Network Connections > Advanced menu > Advanced Settings), all of the PCs can see the Dell printer and all of its network printing and scanning functions work. However, under this arrangement the PCs transfer the video files over the 100MB connection instead of the much faster 1GB connection as desired.

When the Advanced Settings are changed so that the 1GB network connection is accessed first, the video files are transferred over the faster network but neither of the dual NIC PCs can see the 1815dn and their printer tray icons (“Dell Network Scan Manager”) show the printer as “disconnected”.

I'm not a networking expert by any means and may need to do something else to get this to work, however I believe Dell’s printer driver is to blame because there’s a Brother HL-2070N network printer connected to the same 100MB network as the 1815dn and the Brother printer is always accessible to the dual NIC PCs, regardless of which network connection is configured to be accessed first in Advanced Settings. If the Brother printer works under both scenarios, I would expect the Dell printer to do the same. Is this a reasonable expectation or is Brother doing something “non-standard” with their driver to enable this functionality and Dell isn’t?

Assuming the Dell printer driver is at fault and I’m stuck with this limitation, is there a way to configure the dual NIC PCs so they use the 1GB network connection for file transfers and the 100MB network to access the Dell printer? Again, I’m not a networking expert so a simple solution is better (if possible), please. Thanks in advance for any advice.