Complex data merges - Adobe Indesign

I'm trying to work out how to do what seems to me to be a pretty complicated data merge in InDesign, and I was wondering whether anyone had any ideas.

In Excel I have data for a variety of countries, all stored in separate data sheets. Each country has a number of records. Where there are 10 or more records in a country I need to choose the top 10 (there aren't always), and then merge however many there are into a table in a new file in InDesign with various fields being output.

My issue seems to be the extra level of complexity of having multiple records for each sheet that needs merging, rather than one large dataset with a single set of records to be merged into separate sheets.