The first strategy is to acknowledge that no family is perfect. No matter how Leave It To Beaver or The Cosby Show a family looks on the outside, there are always conflicts, differences, rivalries, competitions, comparisons and yes, past stucknesses that are common. If you understand it, it gives you a different perspective on your own.
Secondly, I would suggest to you is to look within. When a good friend of mine perceived an intensity around something with a family member that was disproportionate, she asked me, "What pain/memory inside of you has Life come to heal?" What is unresolved inside of you that this family member is stirring up? Are you holding on to something you need to let go? A memory. A feeling. An event. What is it?
And please understand, it might be an ideal that you are holding on to. Taking a page from my own life, my dad taught us girls to stick together no matter what. However, some of the choices that we made made it impossible. The discomfort that we experienced was when one or all of us kept trying to uphold my dad's belief and force the other siblings to do the same. When I surrendered the need for things to be different--which really is the definition for forgiveness--I could choose who to be around and when. When I surrendered the need for my sister(s) to be different, I took better care of my emotional health - putting it first - and chose not to go to certain family events or, if I did, limit my exposure to them. This removed me emotionally making it impossible for toxicity to find a reservoir.
Lastly, I cultivated an open and willing spirit so that, should a change of heart happen in my sister(s), I would welcome them without trepidation. The key here however is change of heart. If someone is stuck in a reality of you that makes it impossible for them to see you beyond it, there is no reconciliation.
These are the strategies and insight I offer to you. If you need more help, I provide relationship coaching as part of my life coaching suite of services and would be happy to be of further assistance.