Sentence:  He went along with them because the Pack was a <WSD>rainbow</WSD> group — two Italian-Americans, a black man, a Jew (Bishop), and a sometime Englishman (Lawford) — and they were making a point. 
Meaning of the word marked with <WSD> tags:  Made up of several races or ethnicities, or (more broadly) of several cultural or ideological factions.