For SQL 2012 alwaysON, can it support this scenario?
Set up a 12 node windows server failover cluster (A B C ... L)
create 8 availability groups, let them fail over in 3 nodes of the cluster, e.g.
AG1 failover in A B C nodes
AG2 failover in B C D nodes
AG3 failover in C D E nodes
etc.
if this is supported, I guess then it's possible to say for any node in the Windows cluster, it can be at the same time be primaries for some AGs and secondaries for some other AGs (if we don't worry about performance)