Unusual adoptions?

 I think I just uncovered a weird coincidence.

Two different children, biologically related to me, were given up for adoption. Those two children were raised together in the same home as siblings.

However, the two children are from different branches of my family, that at the time, didn't even know each other and didn't live in the same towns.

Still vetting and lots of questions, but the DNA is clear that they aren't related to each but are related to me, and the data is clear that they were raised in the house, both equally acknowledged in the obituaries of their parents.

Wild.