When did this happen? The only people to pin down German panzer divisions in 1941 were the Russians in the Battle for Moscow. The Kingdom of Yugoslavia collapsed in about three weeks after the German-Italian invasion in April 1941.
Later on, Tito's partisans did pin down quite a few German infantry and security divisions, but only after Tito and his Communists had won a civil- war with Mihailovic's royalists in 1942-43. By that time, the vast bulk of the German army was bogged down in Russia and was unable to crush the Yugoslav partisans.
Apart from that, I enjoy Mr Dalrymple's articles, which I find to be well informed.