I am the third person by my full name. My grandfather goes by our shared first given name; my father by our shared middle given name. When the distinction does

I am the third person by my full name. My grandfather goes by our shared first given name; my father by our shared middle given name. When the distinction does not matter, I just use my first given name and surname. I never use the middle given name (if someone called me just by my middle given name, I would not respond). If the distinction matters, then whatever system is in place had better be prepared to use my ordinal (III) as significant, but had better not put it as part of my last name. So I will go by: "A-"; "A- Z-"; "A- H- Z-"; or "A- H- Z- III". I never go by "H-"; "H- Z-"; "H- Z- III"; or "A- Z- III".