From my understanding of the game's architecture, cross-datacenter gameplay would be an absolute mess in terms of latency optimization. (Remember, SE ideally wants players only connecting to their nearest datacenter to ensure players have connections under 200ms so that the game works relatively the same.)

They could maybe link up Aether/Primal or Elemental/Gaia, but crossing continents typically introduces much higher latency and the potential for packet loss. This is all under the assumption that their existing architecture could even cope with sharing instances between them. (Because at that point, just merge the two datacenters into a single bigger one.)

...perhaps you're thinking of them considering cross-world free companies? (Since we've already got friends, parties, alliances, and now linkshells)