If you are using MDSM for management and either VSX gateways or HA clusters in your datacenters, see:
Multi-site and multi-server suggested architecture diagrams and tables
and https://community.checkpoint.com/docs/DOC-2621-mdsm-with-vsx-architecture-recommendations-and-config...
If you are using standalone SMS and gateways in each of your datacenters, you'll have to connect from smartconsole to each of the SMS' individually.
If you are interested in consolidating management of the datacenters, you may consider upgrading your management servers to MDSMs in order to maintain common object database and visibility across all three entities.
This will cost more than your current implementation and will come with additional administration overhead, but may still be well worth it from consistency point of view as well as unified administration and monitoring capabilities.
Regards,
Vladimir