But you can create a Dynamic global object that you can use in a global policy and you can create a Group in the domains, with the same name as that dynamic global object, which you can then fill with local domain objects.
Example would be to allow access to all gateways from your management system through global policy, you create a group called All_Gateways_global in the domains and a dynamic global object in the global policy. Just add the gateways in each domain to the group and the global policy will apply.
Regards, Maarten