I don't think Mazatrol will let you put more than one island in a pocket. You'll have to lie to the machine to get this done.
What I would do is program the islands using slots. Slots don't over travel like a normal line left will plus you can program them wide, or narrow, enough to clear the material between the islands.
I'd more than likely rough the islands out with slots, and finish the walls with rectangle pockets or normal line left programming.
There may be a better way, but I hardly ever use mazatrol for pockets and can't remember all that mazatrol will do for pockets off the top of my head.
The overtravel for line programming is predictable. Most of our machines are tool radius plus an eighth, but there is one oddball that is radius plus .06. It's a parameter setting somewhere that you can change I'm sure.