This might be technically difficult and asking too much of the developers but having a separate closed course during races or at least a way to make other riders without a race tag “invisible” in some way would be a great improvement. One of the great aspects of zwift is the community. There are tons of organized races and group rides. Riding should be social and competative - this is what makes zwift so attractive. That being said, group rides and races can quickly become chaotic with confusing unorganized starts and randomized groups made up of some riders participating in the organized rides and others just jumping in the group while on a casual ride. Or when in a race you run into the back end of a casual sub2 ride of 100+ it can throw off the flow of the race as you frantically try to find the wheel of someone from your group.
Some sort of solution like closed race courses or at least some option to only show riders with the same race tag as you on the right column could really improve and help further develop this exciting aspect of zwift.