You can control which instance of the service to route to by setting up service zones; the intent is that everything will 'just work' (by round robin'ing within a single service zone) so you don't HAVE to set up service zones. But if you want to, for instance, have an EMEA, NA, and APAC service zones, you can control it so that clients will first look for a service instance inside their zone. It's also hierarchical, so you can set up your zones but not ALL services have to have representation in all zones, the messages will get routed to the 'closest' by hierarchy.
OpenDXL
Security Intelligence Sharing