ISRC codes can be embedded into a Broadcast WAV (BWF).
The files are essentially WAVs but with the additional data embedded. As the audio portion remains the same any player that can’t read the ISRCs will just ignore that part of the data. Although the Broadcast WAV format has been around for 20 years and is used in cinema and Film Post Production the format has been coming into play in the audio World during 2014 to help with tracking royalties etc.
Your mastering engineer will be able to perform this task for you but there is free software for you to embed ISRC into a WAV file for yourself.
Can ISRC codes be embedded in a Wav file?