The rules used to go like this:
Every part of your license (i.e. writtens, medical, practical tests) must be done at a school authorised by one single authority. Ratings, however (i.e. IR and type/class ratings) could be done in any JAR country, including a country other than the one which issued your license.
However, I believe the rules are changing, or have recently changed. The best advice is to speak to the authorities in all the States in question, and get replies from them in writing.
FFF
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