In the KLM newsletter I read that within the new fare structure you can combine ALL destinations and ALL different fares if you stay within one of the three IATA zones.

I am far from an IATA expert, what does this one mean?

Hypothetically, can I buy the following return ticket.

AMS-JFK Z-business e.g. euro 2500 return basis
MEX-AMS Q-economy e.g. euro 500 return basis
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Ticket price: 1500 euro ++


Before; the open jaws possibilities were very restricted, so the new fare structure may give at least a lot more flexibility?