Outside Disturbance = Inside Disturbance
Two people are quarrelling.
When I witness that I get disturbed. Address the disturbance.
You cannot change anybody. You cannot change even an iota of a person. He is made by God. How can we change him?
What is the disturbance you have? As per the disturbance you take either the Bach flower remedy or chant the mantras or chant the switch words or heal yourself by doing Mudras.
If you want these two persons not to quarrel then the (internal) disturbances caused by these two people must be addressed first.
There is nothing called external factors. All these things are internal factors, which are reflecting outside. We must be very sure about this.
Even if do not succeed we have to go on try.
Whatever disturbance you have, you heal that. No other tool like shadow self meditation is required. Instead, just address the mind.
Whatever may be your reaction, come out of the reaction. To come out of the reaction affirm, “I accept myself totally”. Whatever comes in your mind, you keep on release them.