well, it is possible, but your crontab lines get awfully long. Cron will only execute EVERY set day, there is no explicit way to tell it every Other set day, so you have to test whether it should run today or not, and in the simple, binary, case like this, the easiest (maybe quickest) solution is to keep track of things with a flagfile.
You can put the logic in the wrapper script above into the cron entry, but, as I said, it makes the entry very long, and difficult to read.