Q: How do I share music in iTunes between different user accounts on the same iMac?

I have an iMac with several accounts.

When I add music to iTunes logged in under my account, it does not appear when my son logs into his account and opens iTunes.

As I understand it, there are 2 iTunes libraries created (one for each account), but for iTunes I really just want the music libraries to be combined or shared.

These libraries are constantly having things added to them (there are some things that are personal recordings, so its not just for iTunes purchases, but other material that has been added to the libraries separately), so I want the sharing to be on-going.

I tried moving the itunes library into a folder on the common HD with full sharing permissions in the hope that it could be opened and referenced by both itunes account sign-ons, but it seems this is prevented.  I can understand why this approach may not work (since it would be possible to have 2 logins "open" at the same time, rather than logging on of one account and logging into the other - and this might cause conflicts).

All other information I have found is all about sharing between multiple computers, rather than 2 logins on the same computer.

Can anyone help me solve this?