Selecting stlink for debug session

I have a complex product where I am running multiple micros with firmware that needs to be debugged. I have 2 stlinks plugged in. But I am stumped at trying to get the VSCode STM32 extensions to target a specific stlink.

My launch.json is using stlinkgdbtarget as the debug type.

"serverArgs" is where I have tried ["-i","<stlinkserial>"] but the debug session launches and in the debug output it prints multiple stlink devices detected, so the session fails.

Is there a way to debug if the serverArgs are even being used?

Is there a different way to select a stlink?