The Apply Modifiers to a Specific Application action accepts either a path or modifiers, usually from the TriggerValue token and performs an action on an application, either opening the file, or activating, hiding, or other actions on the application in the same way that the Applications Palette does.
This allows you to build macro palettes containing macros that act on palettes, and potentially accept dragged files as well if you use the Dragged File trigger.
There is an Application Palette entry in the Macro Library which shows how you can use this facilities to create a palette with a fixed set of applications and similar behaviour to the Applications Palette.
You can default to Hide Other Applications When Switching in the action (gear) ⚙ menu (v11.0+).