Addressing a formal letter to multiple people with unknown names

Solution 1:

For posterity, here is the bounty message I wrote to get more attention to this question: "As a parent and taxpayer, I would like to address a formal letter (starting with "Dear") to nine members of my local Board of Education. This is an elected body and has a mix of genders. I don't want to have to write out all nine names. I am hopeful my situation is subsumed in this question. I am starting the bounty because the existing answers did not receive spectacular votes, so I'm unsure whether @Sanctor's [answer][1] can be relied upon. (The other existing answer only addresses a special case.)"

This was originally contributed by @JOSH. I was going to award it the bounty but I couldn't, because he removed his answer. So I have reposted it here

To address the members of a Board:

Dear Board Members

is an appropriate form you can use.

(www.businesswritingblog.com)

Solution 2:

Only one person at a time will read the letter. Dear Sir/Madam will address each person when it's their turn to read the letter.

Solution 3:

If they're all in a graduate program, Dear Student would seem obvious.

If the correspondence is to members of a body individually, perhaps asking each for his own opinion, then Dear Board Member would seem obvious, although that partly depends on what kind of membership of what kind of board. For members of the board of a company, Dear Director.

If the correspondence is to a body collectively, perhaps giving it your opinion, then Dear Members of Boardname might seem obvious; Dear Boardname would be better. Again, that partly depends on what kind of board. If it's a British limited company such as Bucks, Mega & Cashgrab then Dear Messrs Bucks, Mega & Cashgrab might be obvious.

Styles of address and salutations are very well covered in, for instance, Debrett's Correct Form and several big, church-bible sized variants of Webster’s Dictionary - but mine being stored in an attic since the WWW snuck up, I find the question too elusive for Google.