No not really, at least not live, only in demorecord playbacks where you can edit the actions.
What happens is when you hit the emote 'dance', it sends a command to everyone who can see you that 'this character is dancing so animated it' but it relies on each person's computer to actually render the dance. So it can never ever be totally synchronized. Even if you do the count to 3 thing, it may look even on your system but it could be different on everyone elses. NOT to mention characters of different heights dance at different 'speeds'. And since the slider for height is imprecise, unless you were at the extreme ends of the height slider (tallest or smallest), or at the default, your dance speeds would be different.
But in a demo record, if you edit it, you can set everyone to do the same dance at the same time. 
Don't ask me how to do that though
Is it possible to Syncronize Dancing with other players?
Is there a better way to do this instead of telling the other players "ok, dance on the count of 3."