To fulfill your requirement may be `returns` may solve it. 

      function revealWinners() public returns (uint) {
            for (uint id = 0; id <3; id++) {
                Item storage currentItem=items[id];
                if(currentItem.itemTokens.length != 0) {
                    uint randomIndex = (block.number /
                    currentItem.itemTokens.length)% currentItem.itemTokens.length;
                    uint winnerId = currentItem.itemTokens[randomIndex];
                    return winnerId;
            }
        }
     }