Engagement Party Thank You Engagement Party - Thank You Notes?

Engagement Party - Thank you Notes? - engagement party thank you

Recently, we had a lunch in his commitment, no gifts. We have different gifts, of course, thank you, I will write you notes. What is the proper etiquette for writing thank you notes to guests not bring gifts because they respect our wishes? I think I should write, thank you to all those committed to the dinner, whether or not brought a gift. Help!