Complex sentence: He now rather was part of an international "gang" of sprinters, many of whom were close friends; especially Belgian Jef Scherens and French Louis Gérardins, together with Richter known as The Three Musketeers.
Split into simpler sentences: He now rather was part of an international "gang" of sprinters, many of whom were close friends. Especially Belgian Jef Scherens and French Louis Gérardins were known as The Three Musketeers.