Is there a way to specify the artifacts for export in the Excel add-in so that only a select few are exported?
You can use the "IN" argument in your filter. The "IN" argument will then list a comma-delimited values wrapped in double-quotes.
Examples are:
(FormattedID IN "F1,F2,F3")
(Name IN "Early Story,Late Story")
Here is a full examples exporting only the features whose FormattedID are any of: F1, F2 or F3.