Hey, guess what? If you're really serious about it, a 12 Step program can help you out.
Someone directed me to Al-Anon a few years ago, saying, "It'll help you learn to deal with people."
Al-Anon groups are traditionally there to help people whose lives have been affected by someone else's drinking or drug habit, BUT where the books say 'alcohol,' you can simply substitute with 'people, places, and things.'
It takes strength of characted to go through this stuff, though. You'll want to find a sponsor eventually, maybe, to help you get through the stuff, but only if you can handle brutal honesty. This actually begins with brutal honesty with yourSELF.
You obviously see something wrong with your grudges, otherwise you wouldn't be here posting about it, right? So I think you'll be okay. If you can devote the time to yourself, all it takes is some insight & a lot of good reading & journaling; I used to sit in a restaurant for a good 6 hours every morning drinking coffee & writing, and it's really amazing what it did for me.
Look into it.