infinitefaith - Do you live with these family members? And, if you do, do you have a room/private space to retreat to?
As for you, In general and simply put, your undesirable reactions(anger and irritation) will not go away unless you do penance(change your lifestyle).
The closer your relationship is to God, the easier it is to communicate with him. A divine answer/solution to a problem/situation(daily relations with enemy family) will come to your aid faster, and sometimes without a prayer. Trust me, desire and seek to obtain that.
And, I think that God uses the devils(these humans you speak of) to tell us we are not living a penitential/pious enough life. We are to bear fruit unto life everlasting, and God prunes us to that end. If we do not react properly, we can be cut off. But, that is parable. Just think of advancing in holiness(slow and steady). Avoid going forward until you are sure you will never go back. But, sometimes it is unavoidable. All things are lawful, but not all things are advantageous. Pray on that theme in your life.