Thank you for putting it better than anything I was thinking ofI consider Catholic Christianity to be the one true faith. To say that other religions lead to eternal life is not, in my opinion, doctrinally correct. Insofar as other religions are consonant with the Truth which is definitively revealed in Christ and entrusted to the mission of the Church, these other faiths may indeed assist people towards eternal life- but not per se, only through Christ.
That is a pretty simplistic understanding of the command...What if you're a Masochist?
Should you still "Do unto others as you would have them do unto you?"