There are always ways, but none that I would advise.
I know it's a royal PITA, but except for the very fortunate few that got lucky we have all been there. As in real estate ground loops are all about location, location, location.
As a few of us told you in your other thread, it is a matter of finding the right ground point and it is rarely an easy task. Sometimes the places that seem like the best (grounding at the same point as your amps) are the worst, and other times the worst seeming places work the best.
No matter where you ground, you need to make sure of 2 things.
1) You are grounding to bare metal (scrape paint away).
2) The ground line is short (no more than 6" is a good rule of thumb).
Have you fixed you power wiring yet as discussed in the other thread? Given your inexperience with this kind of stuff (again, we've all been there) I highly advise you invest in getting someone else (a real car audio shop NOT some big box store). Go to a few and try to discuss what are doing and what you want out of the system. If they don't want to talk beyond giving you a work estimate or trying to upsell more work/equipment, move on to one that will spend time helping you better understand the benefits and limitations of what you are asking for. Those shops are out there and the knowledge you gain from them is well worth the money you spend on their labor.
At the same time they fix your power line, they should also be able to work on your ground loop issue too.