It should be possible to filter replication using GTID domain IDs. This could take a number of forms. These could be implemented using system variables, or could be implemented as part of CHANGE MASTER TO.
It would be convenient if there were options to do the filtering on either master or slave. Filtering on master would cause the master to send only events for domains that the slave wishes to accept. Filtering on the slave would cause the master to send all events to the slave, and the slave would discard events for domains it is not interested in.