Oh NO!

I am SO sorry to hear you are having trouble with Zeus! I can hardly believe it, he seems like such a sweet one.

How long has it been going on? Do you think he might be jealous because he doesn't think he is getting enough attention? I know some people don't believe that dogs experience jealousy but I sure think they do,and I think they will do some pretty stupid things to try to get extra attention, including being aggressive.

Which is terrible. And I am not saying that is what Zeus is doing, but just wondering. Maybe with the addition of little Smudge recently?

I am here to help you and support you, I wish I had some good advice. For now maybe you can buy some time and keep him separated from kids for a while (If that's possible) while you try to work something out and get to the bottom of things. Don't give him the opportunity to harm anyone during this time, especially if he has started to make a habit out of the bad behaviour.
I am trying to think of something to say to make you feel better, but I know it is so hard!!! Hang in there! Maybe you can sit down and have a talk with him? You'd be surprised what you can pick up from just sitting quietly with your dog and trying to understand what is going on in their mind! Maybe he just needs some one-on-one time???
I hope something can be worked out!!!