2 ips, 2 multisite installs? or not?

Hi, I am using the domain mapping plugin on my multisite network. My hosting plan has given me 2 ips on my vps. I want to build 2 completely separate networks, about 2 different topics.

Do I then need to have 2 separate wordpress installs, 2 databases and each running off its own ip? What would that look like on my directory - right now my first network is running off the root wordpress install, at ip address #1 -- how would i configure things to have another network running at ip address #2? I have access to cpanel, etc. so I can easily create a second database -- do I need a second copy of wordpress then, or can I just add the database (i would prefer not to use multiple db as I see a lot of questions about this conflicting with supporter, etc which I intend to use for both sites (but separately). Since i am already paying a lot for hosting, I would love to run both networks effectively under the same hosting account.
Thanks in advance,
cmccb