How to add dedicated backup network to existing cluster

Hi Guys,

I have a 2 node SQL cluster that is setup for both SQL and file system backups. Currently the SQL backups run over the production NIC which is something i'd like to change. On the other hand the file system backups run over the backup NICs. so my question is how do I go about adding a backup network to the cluster and creating a virtual IP for the nodes to share?

The nodes are setup with the following ip information
Node 1
NIC 1 (PROD) = 10.1.2.10
NIC 2 (HBEAT) = 172.16.2.10
NIC 3 (BKUP) 10.1.200.10

Node 2
NIC 1 (PROD) = 10.1.2.20
NIC 2 (HBEAT) = 172.16.2.20
NIC 3 (BKUP) = 10.1.200.20

The cluster name responds on 10.1.2.30 where as the SQL instance responds on 10.1.2.40.

The production nic's are setup to allow cluster use
The Heatbeat NIC's are setup for Internal use
and the backup NIC's have cluster use disabled

Ideally I'd like to be able to do the following

Backup SQL using a shared IP on the backup networks i.e. 10.1.200.40
Backup the file system of NODE 1 using IP 10.1.200.10
Backup the file system of NODE 2 using IP 10.1.200.20

Thanks for the help guys!!
Robbie