I am very happy to hear that you & your friends are having a lot of fun playing the game! Likewise, I have to say.
What you've described is indeed very good feedback and I can indeed imagine that in some situations, a squad/party of only a few people doesn't really work out if you've more people where you want to play with than there is space for in the party/squad.
I've been chatting a bit with a few people, who also happen to be massive Battlefield fans, and while it is no proper solution, maybe the following method can help you out a bit like some sort of a workaround:
(Please note: it also does seem to work in All out Warfare, but once the match is over, players will be moved to other servers, so it's most ideal for Portal games for example.)
To get everyone on the same server.
- Add Each other as friends on Origin or as EA Friends in-game.
- Start a party, by clicking the social tab in the right corner.
- Invite your 3 friends to the party.
- Join a server.
- Once everyone has joined a server everyone leaves the party, by going to the menu and social tab again and click leave party.
- Start a new party and start inviting your other friends, your other friend that joined with you can do the same by inviting friends.
- Keep doing this until everyone is on the same server.
Feel free to let me know if this has worked out for you or not.