Hi,
I'm afraid that (to my knowledge) that is not possible.
You must look at it from Shiny's general perspective (this is not a very technical explanation beware
): If several things need to be updated in one user action, the output should all appear at once to avoid conflicting results. In your case that wouldn't be an issue if table 1 appeared before 2, but imagine the code for creating table 2 would alter parameters that influenced table 1, then table one would have incorrect output if rendered before table 2 was finished and needed to be updated again once 2 finished.
In short, I think you have to choose: 1 click and wait, or two clicks and have table 1 first. It doesn't need to be a button, you can also create tabs or something, as long as table two is triggered by something else than table 1.
Again, there might be Shiny experts on here who would know a workaround, so this is just what I got from my experience with it...
PJ