Question How to use scene variables in additive scenes?

I made a whole scene for my GUI only, and put in a bunch of scene variables. Everything works fine on the GUI scene no problem.

Now, when I make level scenes, I sometimes need to pick some variables from the UI scene but bolt doesn't let me. It has a sub-tab in the "Scene" tab but it does jack eff all when I click on it.

Is it impossible to use scene variables when loading multiple scenes additively?

If so, is there a way I can move some of my scene variables into application variables?