Badge "Member Of The Yugoslavian Catholic Union".

[Al-muell]

There used to be quite a large Polish community in Yugoslavia. Heck, during WW2 there were even entirely polish partisan squads as a part of Tito's partisan army. So I see no reason why wouldn't the Polish organize some catholic organisation there?
The origins of polish community there are simple. In austro-hungarian times for some reason (don't remember exacly) some parts of current Bosnia were almost deserted. So, the authorities decided to send there some people who would easily assimilate with the locals. So they took some of the polish inhabitants of the monarchy and moved them there - mainly to the vicinity of the town of Prnjavor. Most of the polish community moved to Poland after WW2 (most of them to the area around the townn of Bolesławiec), but some of them still leave there.

And this wasn't that unusual - e.g. on other ocasion some people from Slovakia were moved to Slovenia. This is still visible if You look at churches in central slovenian towns...