David,
You may want to ask your question in the
+++ RealBand +++ forum section. This FAQ forum section is generally used more by PG Music to relate responses to common questions that PG Music sales and support encounters. I don't frequently use RealBand so with that in mind ...
The short answer is no. RealBand does not let you assign a track color to different instrument groups.
However, you CAN assign a track category or create a new audio category. Track categories include plick/pluck, generic audio, persussion, wind and others. New audio category data includes a track name, picture (icon) file and preset file. Access track and audio categories by hovering the mouse over the mid section of a track (where the default "Untitled" track section is at) and right click to open a sub menu.
Also RealBand has three skins available under Options > Icon Set; 1-Classic, 2-Modern 1 and 3-Modern 2. Each changes the overall look of RealBand.