The reason that the senshi have been split up, is that there's two very large, and relatively separate problems.
1) Both Seleighe and Unseleighe are out in Atlantis wreaking havoc/mischief. This is the Warrior senshi's objective: to protect the citizens and Atlantis.
2) Again, both Courts are after the jewelry and orbs that the senshi posess. This is the Talisman senshi's problem. They have to obtain and protect the talismans from all threats.
For an obscure reason of her own, Gaea has chosen to keep the knowledge that there are two teams to herself. The talisman senshi know a little more the the warriors, but even they are in the dark when it comes to the other teams purpose. Both have pretty much been warned not to interfere with each other, or ask questions. Gaea hints( to everyone's annoyance) that she may tell them why...but later...maybe...