Whenever we go out to eat with a group, we make sure and take cash with us. Usually the whole group gets one bill and everybody puts in cash for it (either directly, or one person puts it on their card and everyone pays that person their portion in cash.)
In our social circle, the bill is always split by what each person specifically ordered (plus a bit towards the tip), not equally (some people do it differently, but that's how my friends work it out.)