The bus transfer MIGHT be a good thing, as it separates them from the older kids and may have been done for security reasons. I'd stay on top on WHO watches the transfers and who's responsible for them.

Is this your first kiddie going to kindergarden?
Don't worry, it'll be the hardest.
By the time your second one goes to kindergarden, you can't wait to drop them off. But not to make light of the situation, it IS a difficult moment, where literal "transfers" of power occur.

Like taking the training wheels off their bicycles for the first time or letting them have the car keys to drive alone the first time at age 17.
You'll see what I mean sooner or later.