Using SMBX2 you can do that... kinda. The game looks for
So you would make a folder called sound_ogg in your episode folder and place a new block-hit.ogg in there to override it.
going int SMBX/data/ini_examples you can copypaste the sounds.ini file into the episode folder and just change what file it looks for, too. That way you can avoid having to create a subfolder, or make it search somewhere else.