That is bad. You are dating 3 other guys behind each others back. As soon as you accept a date from the first guy, you should not be accepting dates from other people. That is shallow and something a slut/player does.
That sounds hard to manage, but if you can do it, you can do it. It might be awkward though if you find that guy #2 is amazing and you both want to spend the rest of the day together but then you're like, "Um, sorry, I have another date at noon, soooo..."