Is there a way to change the Linksys routers to class b?

I have just expanded our network to a class B, 255.255.252.0 network and wanted to temporarily use a Linksys wrt300n router (just for wireless access), but realized that Linksys does not support larger subnets than /24. Have any of you ever run into this and found a way to force Linksys routers to use larger subnets than /24?
I chatted with Linksys and they said that their routers are made to work on class a only.
I probably would be able to do this on a wrt54gl, but wrt300n is all I have to work with for the time being.
Any help is appreciated.

-Roland