I'm fairly new to Drupal, and am using Node Import to take a TSV file and turn it into nodes. I'm hitting a problem, though, with automating updates to the nodes. Again, I'd like to take a Tab Separated Values text file, and load it into my site via Node Import (or whatever else anyone might suggest) and then only show updated Nodes.

Here's a specific example:
I have a Node with the following info:
StoreId Name Address Phone Contact
01 Name1 Address1 Phone1 Contact1
02 Name2 Address2 Phone2 Contact2
etc.

The info pulls into the nodes just fine (Thank you Node Import!), but we also want to process updates to the nodes. So far I have two ideas... figure out how to delete duplicate (previous) instances of the same StoreID, or just save the node with the duplicate StoreID (and new other info) and just display the most current version. In Views, I can get it to show the nodes and everything, but I can't figure out how to only display the most recent version of each StoreID. A view of views would work, but I can't seem to get that to work, either.

Any ideas or other approaches I could take?

Thanks in advance for the help!