I believe the correct way to address for two or more women is:
Dear Mrs. Allen, Ms. Ott, and Miss Day
Dear Mrs. Jordan and Mrs. Kent
OR
Dear Mesdames Jordan and Kent: (more formal)
Dear Ms. Scott and Ms. Gomez:
OR
Dear Mses. (or Mss.) Scott and Gomez: (more formal)
Dear Miss Winger and Miss Rossi:
OR
Dear Misses Winger and Rossi: (more formal)
From Wikipedia (couldn't find a simpler reference):
"Messrs. or Messieurs is a term used to address many men rather than "Mr Pink, Mr White, et al." Messrs is the abbreviation (pronounced "messers") for messieurs and is used in English.
Similarly, Mesdames is a term to address many women or a mixture of married and unmarried women. It is pronounced "medam"."
When greeting multiple women in person I would say "Hello ladies".
Gentlemen:
Greetings!
Dear Counselors:
Dear Messrs. [Last names}
If you are addressing several men and women in a letter, then the salutation can be 'Dear Ladies and Gentlemen'. Another salutation can be 'Sirs and Madams'. These types of salutations can be used for men and women that are on a committee.
The proper salutation for a female can vary depending on their marital status. Mrs. is used for women who are married. Miss is used for women who are single, while Ms. is used for women who are both married and single. This salutation is safer to use if one is unsure of the woman's marital status.
Gentlemen, ...
You could go with "Friends:" or write "hey everybody!"
The abbreviation becomes plural - Drs. Smith and Jones.
Dear Counselors,
In English, the salutation for a doctor, whether they are a medical doctor or the holder of a Ph.D. is the same for both male and female. It is Doctor.