You should be able to just do an:
ifconfig eth0:1 64.191.89.37/24
ifconfig eth0:2 64.191.89.38/24
ifconfig eth0:3 64.191.89.39/24
etc...
There are a few more commands you might want to see if you do man ifconfig, also you need to know the above commands will only work during this boot so when you turn of the machine and turn it back on again you will have to do these commands again, you can add them to your boot files or install a program like webmin (
www.webmin.com) and just do the whole thing from right there.