We brew one at a time....my wife found these rubber rings that have a mesh bag in the middle...I think they might have been tea infusers. They make an acceptable coffee as well, but since the water kind of flows around the grind, you do not get much of an oil extraction...but surprisingly it isn't all that bad.
They almost make cowboy coffee (just pour ground in the water and filter through your moustache) but don't require the facial hair

If we are going more protracted camping, we take a small French press. But it's a single tasker that takes a lot of space...so it stays home frequently. It's also harder to clean...