I did some research and this AV receiver (7.2-channel) would work too; it would power 3 zones:
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https://www.accessories4less.com/ma....4-7.2-ch-x-110-watts-thx-a/v-receiver/1.html
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https://www.avsforum.com/forum/36-home-v-distribution/3034102-1-avr-power-3-zones.html
That's a heck of a deal! ...The best.
If your budget is $300 this is it man, but you live in Europe...former Yugoslavia.
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You need an American friend who would buy it for you, and ship it to you (if that is possible) and with the extra shipping/duty fees. I have zero clue.
But, those models you can check if they are available near you and for how much (best deals).
They are older models (a year or more), so they cost less but that's the use you have for; 3 powered zones.
Here are two more (just below $600):
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https://www.accessories4less.com/ma....2-9.2-ch-x-100-watts-thx-a/v-receiver/1.html
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https://www.accessories4less.com/ma....2-ch-x-120-watts-thx-a/v-receiver-new/1.html
So, something to look for nearby; six AV receivers that would all do what you asked for, and between $300 and $580. The best deal happens to be the less expensive one, for $300 (@ 75% off).