Use specific network adapter for specific address

I have a W7 machine that has an Ethernet adapter and a Wireless adapter. The ethernet is routed through a desk phone, which is then plugged into the wall.

Computer <-> Desk Phone <-> Wall

This makes network traffic quite a bit slower on LAN. There is a specific machine I need to get access to from time to time, but is only available to access on the LAN due to firewall restrictions. What I would like is to have the LAN used only when I RDP to that machine, and the Wireless used for everything else. Currently, when I need to access the protected machine, I need to disable the wireless adapter. I would like to avoid this if possible.

The adapters have different subnet masks, different default gateways, and the same DHCP server

Is there a way to accomplish this via changing network priority, or modifying the hosts file on Windows?

Use routing table.

Add an explicit route rule for the remote machine to go to the wired gateway and change your default route rule to the Wireless gateway (if needed):

In console:

route add -p {network} mask {subnet mask} {gateway}

where {network} is the machine's IP address, {subnet} is 255.255.255.255 and {gateway} is the default gateway for wired adapter. Subnet 255.255.255.255 narrows destination to only one host.

With this all traffic to the remote machine should be going to the LAN.

To display routing table:

route print -4

You need to be an administrator to make changes to the routing table.