Hey Targhan,
Thanks for the quick reply – as soon as I posted I worked out I could simply set a count when playing a sound effect which is decreased each frame until hitting zero.
If a low priority sound effect is requested to be played while this count is non-zero then I simply ignore it.
Sweet spot for my sound effects seems to be setting the initial value of this count to be around 12.
This is a simple enough system but works well for what I need.
Hope you have a great Christmas / Happy New Year!