Mcast Bidir for more than 2 Router

Hi

I am reading a paper about Cisco IPN solution: Interco of 2 ACI Fabric using an IPN (InterPod Network architecture).

It seems PIM for Mcast routing is configured in Bidir mode

I have an issue with PIM RP Phantom configuration:

- How will the RP be elected (Phantom RP/Designated forwarder election means for me that a VIP is advertised for RP basically)

- Cisco gives an example in the paper with 2 IPN routers (IPN for ACI Fabric on site 1, IPN for ACI on site 2)

- Each IPN router will advertise a loopback IP with an IP address in the same range than RP, but with different mask

- For example 192.168.1.1 is configured as RP, loopback 1 on IPN_RTR1 is configured with IP = 192.168.1.2/29, the other one, IPN_RTR2 has loopback1.@IP=192.168.1.1/28, this mean RP is advertised by 2 routers, but IPN_RTR1 will be elected as DF

- This means we are using the longest match rule to break the tie.

- My question: how about I have more than 2 routers ? (more than 2 sites to connect)

- What about the IPN routers on a site that are in a more complex topology (for example I have 2 IPN routers on one site and they must run in VPC or something close ?)

It would be cool If you can highlight me.

BR