Where are the rules for how bards fight other bards, dispelling and counter-spelling each other's Bardic Performance?
For example: The PCs enter into a chamber filled with opposing NPCs. Each side has a L4 Bard.
Paul the PC bard starts to sing to Inspire Courage using Bardic Performance. Nancy the NPC Bard could also Inspire Courage in her side. Could she instead use her Bardic Performance ability to dispel Paul's effect? If so, how is her chance of success calculated?
For Bardic Performance Countersong it says:
Countersong does not work on effects that don’t allow saves.
Could Nancy simply drown out Paul's singing and cancel his Bardic Performance with hers? Where are the rules that govern how that would work?
How do countersongs of a bard work in detail? seems to go into how great Countersong is when used defensively against something that requires a save. Inspire Courage does not ask for a save.