Hey you should feel fortunate. Cox HSI in my area limits our usage to 30 gigs a month down / 10 gigs a month up and 3 gigs down a day / 1 gig a day up max. If you go over that they'll threaten to terminate your service. I switched to DSL after that... I was able to go over 30 gigs a month by myself pretty easily and I share my connection with my roommate (which is not against the TOS). Sharing it with your neighbors is almost definitely against the TOS for your cable internet access though.
By the way, RJ45 is not really the best thing to be using to share Internet connections between homes. Just a word to the wise, most businesses use fiber in between buildings and RJ45 inside buildings because fiber doesn't carry an electrical current. One lightning strike on one of those homes and you could potentially have a surge carried through to all of the people on your network, frying your router, your computer and everyone else's.
(Might want to invest in some surge protectors with RJ45 protection, if you don't already have them).