I have dry navy, black, and salvadorean (dark red) beans. These are all about the same size and shape. I think they would look attractive as a marinated side dish. If cooked together, the colors will muddy. Also, I don't know if they have similar cooking times.
I would like to cook them separately but without wasting energy on multiple burners, or consecutive cooking. So this is my idea: after soaking, put half a cup of each bean into a different empty aluminum can, add water to each, and set them into a couple of inches of water in a stockpot. Is there any reason not to try this? Should I use, or avoid, white-lined cans? Use glass jars instead and if so, must they be canning jars (unlidded of course). Alternatively, will soaked beans cook in a steamer, where they are not submerged? I tend to think not.