Hello

extract the file
and copy eq2ui_mainhud_player.xml with Images folder in your UI folder 
for ex. "........\EverQuest II\ui\myUI"

copy the txt files spell1.txt -> spell5.txt in your everquest2 folder..
start the game .. than open the file for example spell1.txt with a texteditor 
and overwrite the spell bloom with the spell you wish to cast if you click
the button nr.1 at the grp_window.

if you switsch your char open the textfile for example spell1.txt again an 
type the line -> useability spellname ; target_previous <- in the next line
now this char cast the spell...

for example a druid can cast a HOT and an Shaman can cast a Ward on this grp_Member