How to address a letter

[Unregistered]

How do I address a letter to multiple recipients at different addresses and I do not know the genders of each recipient to address it sirs/madames as the names could be used for both male or female.

[hiennguyen]

in this case, I think" lady and gentlement" is more suitable

[Anglika]

How do I address a letter to multiple recipients at different addresses and I do not know the genders of each recipient to address it sirs/madames as the names could be used for both male or female.

We need to know more.

Is this a circular letter going to a number of people, containing the same information in each letter?

If so, use the cc method of listing the recipients at the end, and addressing each letter individually to the name that you have. These days it is not so necessary to be absolute about including an honorific.