Separate notification sound per email account


I installed /e/ 0.13-2020121490326 (Android 9) on my Samsung S8.
For e-mail I am using the default K9 mail client.
In K9 I have more than one account defined. For every account I defined a different notification sound. Unfortunately the default notification sound is used when receiving an e-mail and not the defined notification sound.
How can I accomplish that K9 uses the defined notification sound for each email account?