We got more presents today in the mail. I've never been so happy to see the UPS guy

They were from FI's aunt, uncle, and 2 cousins. 3 separate addresses. Should I send separate thank you notes? I'm not sure that the cousins were involved in picking things out- I just know that on 2 of the gifts it said, "Congratulations! Love, Aunt, Uncle, Cousin 1, and Cousin 2." and on the other 2 it just said from Aunt and Uncle.
So.... To be safe, I should send separate thank yous right?

Mom to D.A (11.09) and 3 beautiful angels (06.08, 03.11, 07.12)