indi volume position and apply opacity by %

A layer name to apply a percent of opacity(o) to a layer at percent of volume position(v) above(a) or below(b), indi_volumea(v%)(o%), indi_volumeb(v%)(o%), replace % with a number 0-100, 100 being full opacity or volume position by percentage. possibly even use the less than(<) or greater than (>) symbols as an alternative to a, and b. infact I insist that those be included if possible
1. indi_volb(20)(20) would translate to "layer indicates volume below 20% makes this layer 20% opacity."
another example could be a group of indicators to get a desired fade of an entity pertaining to volume position.

1. indi_volb(20)(20) would translate to "layer indicates volume below 20% makes this layer 20% opacity."
another example could be a group of indicators to get a desired fade of an entity pertaining to volume position.