
I know this thread is...3 months old but here my answer to Ehren's question:
Go through the Nexus to a Neighborhood that is NOT one that you are a member of. Use the Gahreesen book there. Does it take you to a full Gahreesen rather than a the blocked off limited one?
That version of Gahreesen is hood-instanced meaning that you will link inevitably in YOUR hood gahreesen. Let's make scenarios here...it's something testable.
3 explorers: explorer 1 (E1) is member of hood 1 (H1) , explorer 2 (E2) is member of hood 1 (H1) and explorer 3 (E3) is member of hood 2 (H2). There's also a third hood available in the public links called hood 3 (H3).
Each hood has a KI-version Gahreesen namely G1, G2 & G3.
Scenario 1:
E1 is in H3, he will link to G1
E2 is in H2, he will link to G1 & will be greet by E1
E3 is in HI, she will link to G2
No one will go in G3
Scenario 2:
E1 & E3 are both in H2, they are using the same book, E1 will link to G1, E3 will link to G2
E2 is in H3, he will join E1 in G1 and will be greet by E1
No one will go in G3
So... the book doesn't matter. You can be in any hood in the cavern, the only KI-version gahreesen you'll link to is your hood-instanced one.