See the SFHA 6.0 install guide:
Recommended CP server configurations
Following are the recommended CP server configurations:
■ Multiple application clusters use three CP servers as their coordination points
See Figure 9-4 on page 93.
■ Multiple application clusters use a single CP server and multiple pairs of
coordinator disks (two) as their coordination points
See Figure 9-5 on page 94.
■ Multiple application clusters use a single CP server as their coordination point
This single coordination point fencing configuration must use a highly available
CP server that is configured on an SFHA cluster as its coordination point.
See Figure 9-6 on page 94.
You only need one VIP on the cluster and all the clusters can use this, unless the clusters can't reach this VIP, so then you may have to put the CP server on 2 networks and have 2 VIPs
Mike