Hello rdema1940 -
if you just set up your snipes normally without using a bid group folder, no the second snipe would not automatically cancel if you win the first. However, we have an option where you can create a folder and specify it as a bid group folder and items in such a folder are only bid upon until you win the number of items specified for that folder.
For already existing snipes you can create the folder from the Manage Folders page (from the My Snipes menu) and you must be sure to check the box for "This folder is a Bid Group" while you are setting up the folder as well as set the folder for the appropriate number of items you wish to win. Once the folder is set up, you can select your already existing snipes and use the "Move to Selected Folder" menu and the Move button to put your snipes in that folder.
If you wish to add further snipes you can do so as you create them with the "Add to Folder" pull down in the area where you add a new snipe.
The Bid Group folder items will then get bid on until you have won the number of items assigned to the folder.
Please note that when you are adding items to a bid group folder that items in the same folder must end at least 30 seconds apart to allow eBay to resolve auctions for items that end later to ensure that you only win the number of items selected for the folder.