You can be my guinea pig. Let me know if there are any error messages in your logs. Support for differentiating between team chat is to come. This is completely untested.
Set amx_adminlistenauth to:
0: Plugin is off
1: All administrators (or whichever flag you choose by editing ADMIN_LEVEL) can see all chat
2: Use amx_adminlisten to grant users the ability to see all chat
3: A combination of 1 and 2
4: All users can see all chat