Tour de Zwift - Number of Riders?

I recently completed the Tour de Zwift and thoroughly enjoyed it. I have a question regarding the number of riders entered vs. what you actually see while on the course. Some evenings there was 400 riders listed as having joined the event, but it was obvious not that many were visible while lined up at the starting line or grouped together during the lead in.
That being said, is that 400 total for all groups (ABCD)? I was riding in Group B, so do you only see other Zwifters in Group B? If this is true, is there a reason for this?

You should only be able to see other riders in your category (e.g. B), as well as only the 100 riders closest to you.


Thanks for clarifying that.

Just an FYI that the 100 riders nearby limit applies too all events and free rides on Zwift, but the ‘see your own category only’ can be event-specific. So, there might be some events where you see all of the groups. In this case, though, the riders in each group would appear as different colored dots in the minimap.