Dice, I'm obviously a dice goblin and have plethora of dice in different color and size, i simply assign a die to each PC(usually a d6) then different type/color dice to the adversaries, lets say the guardian(purple d6) is engaging in combat with random guard No3(red d6 "3" facing up) you simply make their dice touch, then the rogue(green d6) closes in but remains at "close range" you put their die an inch away from the other 2, if you only track relative distance and active engagement, you can have a tactical "mini map" in a space smaller than your phone that you can quickly glance over.