From my perspective, the first proposal could be clarified such as "In case of Disaster Recovery Plan crisis, meetings will stand in room XXX". Otherwise the policy sounds like an accountability!
I prefer from far your second proposal. Room XXX becomes clearly a domain, and a policy grant other roles using this room under certain conditions. As I suppose there are some security and reliability issues in the tension behind, this sounds a clear-cut and more consistent option.
Hope that helps,