Thank you letter- help!

I had an interview that I felt went really well, however in my excitement I forgot to write down all of the panel members names, I have one of them prior to the interview. I tried calling the hospital to figure it out and was only able to get one more leaving one name unknown.

I'm kicking myself and am hoping this doesn't kill my chances at a dream position. Question is write one letter or email addressed to interview/recruiting team or don't write one at all?
Writing one letter addressed to all is better than not writing one at all. Since you have the name of at least one member you might address it to them and then maybe add in "please relay my gratitude to the other panel members..." something like that. Just an idea.
Address it, "to all panel members", thank you so much for ...:
Thank you! I sent it out and addressed it to all panel members. Now the hard part...The waiting game begins