2-4 figures in one square

In the system I'm running, 2-4 characters can share the same square (usually just 2). I was wondering if there was any easy wary for Roll20 to deal with that other than just making the portraits small & making them not snap?

Assuming 5 foot squares and maps that are not too big, you could make the squares 2.5 feet on the map and make the maps twice as big 

You could make your map twice as large, and adjust the distance for a unit on the grid to half the size, then put each of the tokens in the 4 parts of the now present larger square.  You could even take an image like this one (scaled to 20x20 units, tinted some color) and drop it over your map to give the "Real" grid separate from where your tokens are sitting. Set your ruler to corner to corner, and you can measure from center to center of the large grid squares easily: