Windows 2008r2 clustering multiple network question

I want to build and active/passive 2008r2 cluster that will run netbackup 7.5.  I have mutilple networks that must connect to the cluster so that each subnet will be able to backup.  My question is for each subnet, do i need an ip for each cluster node plus a VIP?

I would imagine that each vip could be listed in dns as vip1.domain.com vip2.domain.com vip3.domain.com and so??

But, that doesnt make sense to me because for netbackup all networks need to take to the same vip name from all subnets. 

Hopefully someone can answer this for me...Thanks!!