Need help with macro

Lately I’ve been trying to optimize my Holy spec for glimmer of light build. In order to do this I need ready access to my crusader strike. To make this simple I macro’d it to target a nearby enemy, make it my focus, and cast crusader strike on my focus.

Is there anyway to make this macro not change my target if I already have a focus on an (Not dead) enemy? I’m aware I could very easily set this up with a second button, I just want to have this all in one button.