This is a medium priority feature request that can probably be implemented in less than an hour.

Adding the decay option to the sound_id_stop will allow a large number of additional sound effects to be possible from TRP3 extended at a limited risk (the only thing I can think of is that someone would use it to play a sound that can't be stopped anymore from the sound history table, because the handle was officially closed already, but since these are not local sounds, but only sound ID I doubt this is very dangerous).

I have tried creating this myself, and succeeded by doing the following modifications (my knowledge of github is limited, so I wasn't able to package them all neatly together).

https://github.com/anuvogelat/Total-RP-3/pull/2/commits/c41c3ba50a810121563c036c6f6c4f5df4fe71ee
https://github.com/anuvogelat/Total-RP-3-Extended/pull/4/commits/5257ae3c31791f889e3a326f5d5030269f261da9
https://github.com/anuvogelat/Total-RP-3-Extended/pull/5/commits/003308b7e5c1254d319172a105a98d3eb6ebf251
https://github.com/anuvogelat/Total-RP-3-Extended/pull/7/commits/2b8d027db0d4e31309c0c3176bf0425db704e254
https://github.com/anuvogelat/Total-RP-3-Extended/pull/8/commits/edb01ae5cbf5d4a70a5f458464a465b1427b5fe3