A friend of mine uses the biodegradable E6PR™ six pack rings (https://www.e6pr.com/) and had his father create a piece of wood to support snapping the cans onto the rings. They are very tough to get in, so need some sort of support. 

The wooded solution was okay, but started to degrade fairly quickly, so I designed this print to use as well.

The print sits on the table and the cans are inserted upside down into the ring holder. It should be mounted to wood, or have felt pads on it to help it not slide around, but that is up to the user to figure out. #8 screw holes have been included. They can easily be blocked out using your favourite modelling program.

(Will add in-use photos shortly)