Right you are, I read that too fast. My bad.

But this sounds like much more fun than actually play WoW right now, I decided to put a bunch of thought into it and came up with two possible solutions.

Idea#1:
First I created a macro and placed it on an action bar.
/cast spell 1
Now the main macro is this:
/click [@focus, exists] MultiBarLeftButton1
/stopmacro [@focus,exists]
/cast spell 2
If you have a focus it casts spell 1 and if you have no focus it casts spell 2. Change MultiBarLeftButton1 to the button you place the first macro.

Idea#2:
Create two action bars, one filled with the spells you want to cast when you have a focus, the other filled with the spells you want to cast without a focus, then you use these macros to set/clear focus.
/setfocus
/changeactionbar 2
/clearfocus
/changeactionbar 1