If you're co-locating them all, then it's easy: EQ the group as one with a single EQ channel.
If you're putting a pair in one location and a pair in another, then that's a little trickier. If you have a symmetrical shoe-box-type room and are using symmetrical placement (e.g., one pair on one front corner, the other pair in the other front corner) response should be the same for either location, so once again you can EQ them all with the same set of filters from a single EQ channel. If you're going for asymmetrical placement in a symmetrical room, you'll probably want to EQ each pair separately (two EQ channels).
For a non-symmetrical room, again with a pair in two locations, with either symmetrical or asymmetrical placement, response will most likely be different at each location, so you'll probably need to EQ each pair separately (two EQ Channels).
If you're locating all four in four different locations, that can be a nightmare, depending on the room. It might be best (read easiest) in that case to just EQ them as a whole (i.e., one EQ channel).