You will need to set the MAC address for each
of the virtual machines statically as described here:

Setting the MAC Address Manually for a Virtual Machine

Once you have them set statically, you will simply need to
provide us with a 1:1 or 1:many mapping of MAC to IP address(es).
We just need to make sure that everything is accounted for, so
we don't have users trying to hop MAC addresses, switch IP's,
etc.
-----------------------------------------------

For example:

00:50:56:3F:50:50 - 64.85.161.145
00:50:56:3F:50:51 - 64.85.161.146
00:50:56:3F:50:52 - 64.85.161.147

Hope this helps.  Please let me know if you have any
questions.

Regards,