I think perhaps a LoadSound LUA command is perhaps the best way to go here, as it will mean unlimited sounds are possible per single script and avoid confusing the main UI with too many additional properties. Of course, the danger is that every entity that uses the script might need to hold unique instances of the sounds being dynamically loaded (thus a memory hog) so it might be smarter to have a 'global sound index' to promote common sound slots and careful management of the sounds being used per game level.
PC SPECS: Windows 8.1 Pro 64-bit, Intel Core i7-5930K (PASSMARK:13645), NVIDIA Geforce GTX 980 GPU (PASSMARK:9762) , 32GB RAM
