Windows – Static Routes Without Specifying Gateway

I have the following scenario:

Computer A: 198.51.100.8, netmask 255.255.255.0
Computer B: 203.0.113.9, netmask 255.255.255.0
Both computers are on the same LAN segment; no default gateway is specified in either case.

To get these two computers to communicate with each other, I've added two static routes, like so:

route add 203.0.113.9 mask 255.255.255.255 198.51.100.8

However, I would prefer to add the static routes by specifying a network interface, instead of by specifying a gateway IP address.

This is possible with Linux by using a command such as:

ip route add 203.0.113.9 dev eth0

and similarly in FreeBSD:

route add 203.0.113.9/32 -iface fxp0 -cloning

However, I'm at a loss of how to do this with Windows. Ideally I want to do something like:

route add 203.0.113.9 mask 255.255.255.255 if 2

but that merely prints out the usage for the route command, which tells me that I'm doing it wrong. I've also tried to use netsh, which tells me:

> netsh routing ip add persistentroute 203.0.113.9 255.255.255.255 "Local Area Connection"
Specify the next-hop for non point-to-point interfaces.

Any thoughts or suggestions?

Update: When I originally posted this question, I was using Windows XP. But I neglected to mention that.

I'll leave Grizly's original answer, as it is correct for my original question. But if you're using a newer version of Windows than XP/2003, give one of the other answers a try.