Hi Juan,
There isn't a mechanism to change the inventory name. However, based on your 2nd question, I'm going to suggest you consider the segmentation feature within the portal. Segments are created by you based on "rules/patterns -- based on device attributes such as IP Address and Hostname". As you might imagine, the segments are a "subset" of an inventory and the content of the segment is based on the rules/patterns. For your need, consider creating/defining a segment for each country/region.
Bobby