Formal:
* Bonjour mesdames: This is the most formal way to greet a group of women. It literally translates to "Hello ladies."
Informal:
* Salut les filles: This is a casual and friendly way to greet your girlfriends. It translates to "Hi girls."
* Coucou les filles: This is a more informal and playful way to greet your girlfriends. It translates to "Hey girls."
* Salut mes amies: This is a bit more formal than "Salut les filles" and shows that you consider them your friends. It translates to "Hello my friends."
You can also use a combination of these phrases, such as:
* Coucou mes amies!
* Bonjour les filles!
The best way to say "hello girlfriends" in French will depend on your relationship with the women and the situation.