sFTP to docker volume

I’m configuring a server that will host several websites. Each website is stored on a docker volume. I want to give each site owner SFTP access to their web root to upload files. What are the best practices for setting this up? The problem I’m running into is that the volume is owned by root, but for SFTP to work properly the _data file for each volume needs to be set to the client’s user account. Can someone point me to documentation explaining how to setup SFTP access to a docker volume in a secure fashion?