Custom Command in WPF to allow dependency property value change in "realtime"

Question

I have a scenario where in my custom control I have a custom Dependency Property called MinValue of type int.

I want to allow the user to change that value via keyboard input Ctrl++ (increase) and Ctrl+- (decrease). I undertand this can be done with Commands, but am clueless as to where to implement those Commands. The user should be able to use the beforementioned keyboard shortcuts no matter what control in the Window has focus.

I think I would have to implement the Command in my custom control because only that control knows what to do with the keyboard shortcut, but since I have a listbox full of custom controls, and each should handle the shortcut, I'm not sure how that would work. Any pointers? Thanks as always!