Well, you can look at this several different ways. First, there are the good guys and the bad guys. This changes throughout the play--at first, the good guys are Banquo, Macbeth, and the loyal followers of Duncan. The bad guys are MacDonwald and his rebellious crew who were defeated.
This changes, of course, when Macbeth crosses over to the dark side and becomes obessessed with becoming King. Therefore, he takes MacDonwald's place as rebel and usurper, thus killing Duncan, Banquo, and many other "good" people. The good guys now are Malcolm and Donalbain (Duncan's sons and rightful heirs to the throne), MacDuff, Kind Edward of England, and anyone against Macbeth, who ultimately is left standing alone until he is beheaded.
Another way to look at it is the gender issue--Lady Macbeth and the witches (whose gender is rather cloudy when you consider Macbeth's quotes about their beards) are definitely used as catalysts to Macbeth's downfall. He is also protrayed as womanish (too full of the milk of human kindness) while his wife is mannish (able to conceive man-children only) until guilt carries her away and she commits suicide.
Still another way to look at groups and individuals is the supernatural vs. mortal. The witches, Hecate, and the ghost of Banquo as well as the visions they show to Macbeth are definitely worthy of mention. Without them, Macbeth may have never been pushed on to do the things he did in the play.
I would have to say that it is between genders and gender identity: groups that are male, female, and what was in between.
The witches seemed to be women with beards. Lady Macbeth wished she was a man to carry out her plan. Macduff was not "borne of a woman."
I think the play centers a great dela on identity of gender.
Perhaps the most amazing group is that of the witches. On a couple of occasions, the queen of the witches, Hecate, join them. Ross, Angus, Lennox and others constitute a group of Scottish nobles who accompany the kings, but later in the play we see them desert the tyrannical Macbeth. We further notice a group of menials like the porter, the messengers, chamberlains, the gentle-woman etc.A group of three murders is appointed to eliminate Banquo & Fleance.Towards the end, a group of rebels wage war against Macbeth.
Among the individuals, the most exceptional is Macbeth himself. Then there is the collaborator in crime in Lady Macbeth. Macbeth's compatriot in battle, Banquo, is yet another key individual figure from the beginning. There is Macduff, an example of active goodness as opposed to Banquo, serving as an instrument of nemesis for Macbeth.