Hi Fran, this might not answer your set analysis question directly but it should get you down the road.
Also, I posted this because I could not find the answer elsewhere on this same/similar topic.
////////////// pull in a field from a table...MemID in my case.
load Distinct MemID Resident sca;
////////////// use that field to create a random color (or of course build your own static RGB's with an inline table
//Rand() as random,
) as MemColor
//////////////////////////// Then in the Marker Icon box this is the formula using the field from above
='autocolor,' & MemColor