In the most recent development version, you can insert TXT, GEO and STL geometry files into your existing geometry. You can even choose between merging them with the current superstructure, or treating them differently. Below is a simple example created by merging 3 files:

Once the geometry is inserted, you can copy or move it. Rotate, mirror and flip options are coming after the Easter break! Until then, check out the complete changelog or just download it!