I had my baby before I got a chance to write thank you notes for a gift card shower my coworkers gave me. I got several gift cards from groups of people but I don't know exactly who contributed to all of them (example: first grade team), I can only assume all on that team did.

I usually am pretty traditional and like to write an individual thank you to each person who contributed. In this case should I...

-still write an individual thank you if names are listed on the card
-if names aren't listed and it is from a group, write the group 1 thank you note
-send an emailed thank you note and blind carbon copy who is on the email (for example 1 gift card is for $100 and is from about 20 people)

Or any other ideas?