A little bit of macro help.

[Twoshoes]

Hey guys i just need a little bit of help writing a macro
What im trying to do is make a macro that will cast on mouseover, if no mouseover on target, if no target on focus target and if no focus target on myself.
I can get it to do 3 of the 4 but i can't work out how to add in the focus target.

#showtooltip Sacred Shield
/cast [target=mouseover,exists,help] Sacred Shield; [help] Sacred Shield; [target=Focus] Sacred Shield; [target=Player] Sacred Shield

that does not seem to work and i have no idea.
Thanks for the help.

[lawomous]

#showtooltip
/cast [@mouseover,help][help][@focus,help,nodead][@player]Sacred Shield