Party1target was the common PVE method of assigning targets. The problem is that as soon as you try to PVP and have your clones follow someone else you realise the flaws. This is why focus has become the defacto standard.

Some of us like to overload the functions and use Vyndree's method in macros
Code:
/cast [target=focustarget, harm][target=party1target, harm][] spell
This lets you use party1 when no focus is set (or focus is being used for CC), focus when needed (eg battlegrounds) and will use assigned targets if neither of the previous have an [harm] target.