How do i go about becoming friends with them?

[HPfangirl]

Ok so theres a group of people that i want to be friends with and i talk to some of them already (they're in other classes with me and most of them are also in marching band with me also), one of them is my best friend but i want to be friends with ALL of them, if that makes sense (sorry this is kinda hard to explain). Like i want to be part of their circle, you know? and they seem to like me, i fit in with them, but its kinda like im not entirely included yet. Like they'll go and do stuff without me knowing like going over each others' houses and stuff and post pics and stuff on facebook and i cant help to feel left out even though i KNOW that im not fully a part of their group yet. So here's my question: How do i go about fully joining their group, like gradually insert myself into it or...?
PS I'm 15 yrs old and a sophomore in high school. They've been an established group of friends since at least 8th grade (i didnt go to middle school with any of them) and i wouldve been friends with them freshman year but i was really awkward as a freshman cuz i didnt know anybody

[Gina]

Try to get to know them individually. I had that problem too.

[?]

Ask your bff if you two can go out to like an amusement park or something, and say she can invite her group also along. This way you would have enjoyed a fun experience together and it would make them get to know you a bit more. All the best !

[Danielle]

Say be like hey guys next time you guys do stuff be like can I join? Or just texts them ask them there Favs and talk to them like you have known them forever. Just be like hey guys we should all do a moive thing or ( replace moive with something you think thy like) best shot be perstaint and just texts them and always ask them what's new in there live. And be like next time you guys have a sleep over can I come? they Probley want you there so don't feel left out .