Hi Juan,
You can create additional Data Sources in Jaspersoft pointing to a different from PPM and DWH database. You can then create a Domain based on this Data Source and include in your Ad Hoc Views and Reports.
I would advise you to ensure you have additional bandwidth on the server to support your other applications. As Andy advised you above please note this is unsupported by CA Support if you encounter any issues.
One other thing I thought I would mention : Please use another organization (tenant) for your other reporting purposes, this would avoid any potential problems during upgrade where OOTB data or custom reports may get overwritten. It's best to keep the Clarity tenant separate, this would make it cleaner, avoid you running into some issues, and facilitate the backup.
Kind Regards
Nika Hadzhikidi
CA Technologies
Principal Support Engineer