He can do it by two methods:
if(pc_isequipped(sd, 23111) && pc_isequipped(sd, 23112) && pc_isequipped(sd, 23113))
Here all the items should be equipped to trigger the next steps.
Or
if(pc_isequipped(sd, 23111) || pc_isequipped(sd, 23112) || pc_isequipped(sd, 23113))
Here any one of the item if equipped can trigger the next steps.