Usually to control an import action we filter the source. I am very curious why you cannot touch the source module ? Creating a saved view is not a disruptive process.
Whatever you do the the target module (filter, sorting, hiding), it will not impact the import action. However you can change the mappings of the import, for the dimension of "country" as " Ask each time the import is run". Or you can manually un-map the others. See below
As @nathan_rudman already pointed out that creating saved view is not a disruptive process and you can easily achieve this by having a saved view in Module A.
Approach 1 - Create Saved View by applying a filter on one particular item (let’s say Italy in this case). Make sure the filter is Boolean in nature.
Approach 2 - You can also do it @JaredDolich way. Create a list subset for One List Item (Italy in your case) and use that subset as a dimension in Module B and pull the values from Module A to Module B
Approach 3 - You can also achieve this by creating a dimensionless module (Module C)with one line item (List formatted - Country) and select the drop down as Italy. Create Module B with no dimensions and pull the values from Module A to Module B and using LOOKUP on Module C Line Item.
All the approaches will solve your problem but personally I will take approach 1, then 2 and last but not the least approach 3.