Tolumnia potting options

[jmrathbun]

I just received three different Tolumnias, each in its own 1.5" pot with small bark. I want to repot these on medium lava rock as recommended in a recent Orchids article. Of course I don't have any 1.5" pots and they don't stand up very well anyhow (nor do I have a good place to hang them). I have 3", 4" and 6" pots, any one of which is big enough for all three orchids to share one pot. It looks like these are blooming size, because I see an old spike on one. Their varieties are
Tolumnia Genting Orange
Tolumnia Genting Sunray
Tolumnia Tequila Sunrise
So what do you think? Can they share or should I leave them alone or give each its own pot? The surface area of a 1.5" pot is around 1.8 square inch, the 3" pot has 4 times that area, the 4" pot has 12.5 square inches and the 6" pot has an area around 28 square inches. The volume goes up exponentially too, of course, but I'm not sure how important that is with inorganic media. They have a LOT of air roots!