What inclusive phrase should be used in formal letter writing instead of “Dear Sirs”?

People of all genders work at different institutions.

Is there a way to address people that are members of an organisation in a way that isn’t long winded or clumsy?

I am struggling to find an alternative phrase to one that basically says “Dear Men”.

Should I write “Dear Sirs, Madams and everyone else”?

At school we were always told to write “Dear Sirs” if we were writing to a group of people.

How do I write “Dear Everyone at this address” in a formal and concise way?