You are close. The following query returns the list of interfaces for the affected node
${SQL:Select FullName FROM Interfaces WHERE NodeID=${NodeID} }
but the SQL macro always returns only the first row, first column. To return the entire result set, you can modify the query as below with a ; delimiter
${SQL:Select FullName + ';' AS 'data()' FROM Interfaces WHERE NodeID=${NodeID} FOR XML PATH('')}