Probably can't have both between the same pair of arrays, maybe.
There used to be a limit of only one RC pairing per node pair, so might need a 4 node to sit in the middle of two 2 nodes.
There are a lot more options now regarding RC links per card and mixing host/RC on the same card plus doing one port pair for sync and another port pair for async and even a teaming style of multi ports per link.
What code are the arrays on?
EDIT: Looks like in 3.3.1 you can have up to 2 pairing per node pair, so a 2 node system can talk to up to two other arrays via any mix of RCIP/RCFC/FCIP.