Multi domain access

We have an isilon system with one zone(system) currently and joined to one domain.

Now we have a requirement to share data for users from another domain. How can we acheive this requirement?

I read that access zone concept can be used but i would like to know if we need make any modfication to isilon smart pool settings or create a new one with IP address from new domain. I have learnt that an AD trust has been created between our primary domain and new domain. Appreciate if you guys can provide some suggestions.