Create any item and make it call a function. Then,
function script JobBox {
setarray .@Jobs$[0], "Rune Knight", "Warlock", "Ranger", "Arch Bishop", "Mechanic", "Guillotine Cross", "Royal Guard", "Sorcerer", "Minstrel", "Wanderer", "Sura", "Genetic", "Shadow Chaser";
setarray .@Items[0], <Rune Knight item>, <Warlock item>, <etc.>;
set .@menu$,"";
for(set .@i,0; .@i<getarraysize(.@Jobs$); set .@i,.@i+1)
set .@menu$, .@menu$+.@Jobs$[.@i]+":";
getitem .@Items[select(.@menu$)], 1;
return; }