[IsEquipped more than 1 item]

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.