NT4 Network Routes pls HELP

[SJBTT]

I know how to create network routes on NT servers, but I need to add a route for lots of networks using the subnet - but I don't know how.

Eg.

To create route for network 123.10.100.0 vi a gateway of 123.10.1.1 I would use

route add 123.10.100.0 mask 255.255.255.0 123.10.1.1 -p

But I need to create a route for a range eg:
123.10.100.0 & 123.10.101.0 & 123.10.102.0 etc all the way to 123.10.254.0 all via the one gateway.

I can't use a class B route as 123.10.1.0 upto 123.10.99.0 need to go elsewhere.

can anyone suggest the route - I think it will be something like 123.10.100.0 mask 255.255.154.255 123.10.1.1 -p

Any help is much appreciated.

SJBTT