Could Yugoslavia rejoin again and not break up and why?

I was doing some research for a school project about the Balkans. And when I started studying some stuff about Yugoslavia and the genocide and its breakup and I went deeper and deeper into it and it became clear that it would be much easier to deal with one big nation instead of seven tiny nations (Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Serbia, Kosovo and Macedonia). So, my teacher offered me some extra credit (20 points on my final grade or until it reaches 100%) if I devised a plan to organize the countries into a former Yugoslavia. I devised three plans but each one of them involves either significant help from the US/UK/NATO/Russia, etc and without their further involvement, wars like those from the 90s would emerge again. So my question is how could you merge those countries into one and how to keep it together without foreign military intervention (covert assistance through funds or military arms would be fine) from any country really? And if so, how could you do that? Thanks a lot, people.