This is possible. You can either set a constraint (if that satisfies all needs) in the XLS Export Definition, or what I think is the case you are looking for:
You can also create an association between the main entity of the row you are exporting and the file entity. Then in the excel export java action you can pass the fileobject as an input argument.
In the XLSreport definition (in the app itself) you can then use this association to the main object to only retrieve the associated data.
This means it will only retrieve the data that is associated to the file object. So that means you still need to set the value for the association between the only row you want to export and the file that you created.