I just had a brilliant idea! (Or at least I think it's so.) I've been re-reading all my Eberron books in preparation for a short campaign with my local gaming group, just as a point.
Now, in parts of Sarlona, particularly near the Tashana Tundra, but also in northern Riedra, there are aukaraks, or reality storms, where intense manifest zones sweep across the land. And that's not the only place on Sarlona where there are very weak planar boundaries (there are certain manifest zones guarded by an organization called the Edgewalkers). What if our kalashtar were caught up in one of theses reality storms while on a mission and were shunted through one of the planes to...
...a planar gate in the Shadow Marches, where a group of battered warforged are mostly sunk in the muck and hence overlooked when the rest of their squad had to pull out of the region, some 3-4 years ago, when they were looking for some ancient weapon/eldritch machine that could aid their army/House.
The kalashtar are far from home, and the warforged are far from their army.
And together, they fight crime! Or search ruins for things. Or rob tombs.
All that jazz.
What say thee, group?