Yes, you can assign different time blocks to each item. First you want to create a new time block.
1) Click "Auctions" on the far left > Click on "Manage Auctions".
2) Click on the Name of your auction.
3) Click "EDIT".
4) Click one of the existing time blocks or click "Add new Time".
5) Once your Time block has been created, go to "Items" > All Items. Click on the Blue Pencil to Edit your item.
6) Find the Auction time section and click on the time block you wish to assign the item.
If you would like to add multiple items to a new time block please view the steps on making a bulk edit HERE.