"Jealous rivals" refers to individuals or groups who feel envious or resentful towards each other, often due to competition or a desire for what the other possesses or has achieved. Full definition
I know that Brits, like Canadians, will be subject to the frivolous complaints of jealous rivals when they host the 2012 Olympics. (slaw.ca)
This includes Jews, Christians, and Muslims, all of whom are prone to behave like jealous rivals competing for God's favor, reenacting the first murder in the story of Cain and Abel. (firstthings.com)
But be wary of jealous rivals, who will try and push your tower down with nefarious dark spells to ensure their dominance. (gaminginstincts.com)