I have found two things to be most helpful for my gang of 5.
One is to get *taller* litterboxes. (I don't usually recommend hooded boxes because a lot of cats seem to have issues with them.) You can get those super-huge (10-30 gal. depending on your needs) storage boxes at Target (or similar stores) for $10 or less. Rubbermaid boxes are great because they seem to hold less odor than other plastics, and the ridges on the bottom are low and rounded, easier to scoop and clean. Tall is good because it prevents them kicking a lot of litter out when they dig. Also, for cats who fail to squat sufficiently, or who hang their butts over the edge, it keeps all the "products" inside.
My other trick is to have a small rug just outside the box. This does *not* work for cats who like to *use* the rug! For those cats, the textured rubber mats (made for the purpose) work better. Currently I have a bathmat in series with a small patch rug (like a doormat), and that really helps get the litter off their feet before they head off to their next spot of trouble. Mine all enter and leave in the same spot so it's easy to position them...other configurations might have to get creative!