[arch-general] systemd sessions, su -l, and access to /dev/

Hello. I asked about this in the forum. But it looks like this is a better place to discuss systemd-related issues. If I login to user1 or user2 then try to play audio which requires access to /dev/snd/* , proper access to the logged in user is set by the session and everything works correctly. But, if I login to user1 then su to user2, audio wouldn't work because access permissions are assigned to the session user only (user1). Any idea how to fix this issue?