Click MY CONTACTS on the top of the page
Select multiple contacts in the middle column
Select a group in the left column and click on All up top of the middle column.
On the right side of the page, click Block. To undo, with the same contacts selected, click on Enable.
**Note about downloading rules**
If you disable downloading for a contact, they won't be able to download any promos, regardless of the download settings in a promo.
If downloading for a contact is enabled on this screen, then promo rules apply. Example: One promo might not allow any downloads. One promo might only allow 2 downloads.