Common Goal

Generally I believe that to implement the Golden Rule throughout humanity would take a lot of effort and change on the part of people - but I see no inhibitors to it, I'm looking for a common goal that everyone can share in regardless of their religion.

An admirable thing you seek. I'm too cynical to think it possible. But I think that, given human nature, that any goal you wish to be accepted by all must be a selfish goal. Asking for common sacrifice won't be a sustainable policy, I suspect. The urge to "go selfish" is too great.

Hence the problem ... is there anything that is universally agreeable and individually self-serving? Or are those two things mutually exclusive?

The environmentalist movement -- and in particular the "global warming" movement of late -- comes as close to that as anything I can imagine. It's universal (we all live in the same global realm) and it's entirely self-serving (I don't want to die). However, even that has its problems ... the sacrifices called for always seem to be "their responsibility," not "my responsibility."