Support Voice ID for custom commands

[dangerusty]

Is your feature request related to a problem? Please describe.
I'm trying to use custom command to tell Alexa to use a skill to unlock a door. The skill requires that my voice is recognized for that command. When I try with Alexa media player, the target Alexa device reports "I could not recognize your voice".

Describe the solution you'd like
A way to pass a voice ID with the custom command. Or a way to have Alexa "learn" the voice used by Alexa media player.