Should I become friends again?

oy vey. I have about 4 friends i hang out with in school. L, b, z, and m. z and m are great, i love those guys, but l and b are pissing me off. about halfway through the school year, l got a really manipulateive girlfriend, so now he's completely changed. He started chaning friends, he changed his sense of humor, he changed his taste in music, he even changed his religion, and he abandoned me. B stayed with me, but soon followed because he's weird like that. I somewhat hate L now but i really miss b. What should I do? should I make things "right" wiht l? or talk to b? what should I do?