how do you get return true if something like my party member type "heal me" in a party chat ?
or check it someone in my party says "hi" which returns true, ill say "hello"?
To listen to whats happening in party chat, you'll need to hook into some events. I'd suggest looking at some of the monitoring plugins for some advice on that.
you can do Lua.DoString("runMacroText(/say Message here)");
or something like that, for listening to party chat, your going to have to use a event hook.