For MAME cores, in addition to the ROMs, same games have "Sample" wav files too

... Where to put it?

For "normal" retroarch, these are usually placed under the /BIOS folder structure under each core's own folder.  Which is something like this:

/bios/mame2003-plus/samples/

Is it possible to place these sample .zip files somewhere within the container so they can be utilized to allow these games to run with the proper sounds?