I was thinking along similar lines. There was one purple that I recognised and one blue that would also fit in something like the purple category, but I was one short on blue and it was the only one that would fit.
Since everyone who normally does this has had a go, I'll be more explicit. The blue group one that I had focussed on at the very stary was Rather - thinking Dan Rather. I thrn saw Stern and thought first of all of Daniel Stern, and looked for other Dan/Daniels and didn't know any. Then thought of Howard Stetn, and thought of broadcasters of some connection, same result as the Dans, even though it was closer. Got the yellow and green. Saw the sort of qualufier connection for blue. Was still dead set on Rather as part of the purples. Tried forcing Gross into the blues. Gave up, put Rather in, and got to find put the detailed collection of purples, 3 of whom were like Vienna to me.