well first stop shouting at them. eldest has your genes so any shouting rows will just escalate and eventually lead to withdrawl and alienation, won't they ?.
you have noted there may be a problem and are beginning to solve it, so what a great start.
i find it hard not to be angry at times but anger is just a feeling, you know? you can feel angry without the feeling taking control of your mouth or limbs, surely? it amazes me that no-one teaches feelings in school and how to feel them.
at some point you mistakenly learned that shouting solves problems. shouting is monkey dancing, two animals squaring off and showing who is bigger with neither actually wanting the seriousness of a fight. once you understand it as primal maybe that will help.
when you feel anger and it triggers your primal responses your human form doesn't have the awareness that shouting is not required in the situation. in fact as you are finding shouting often leads to more problems than it solves.
are you not in fact shouting simply to warn others that you have an angry feeling and are not able to process it properly?
so you need to stop it is teaching the kids a bad coping mechanism.
anger usually hides other feelings. you probably have a lot of unresolved emotions from childhood. it's best to talk with a therapist as they have the training. but it's not a one stop talk it through and it will heal deal. therapy can be about unlocking all the pent up rage, frustration, fear, anger, shame,guilt, embarrasment etc which has accumulated over the years and understanding the dynamics of your family of origin.
by unpicking and understanding the emotional response you have learned you can re-learn a better way of processing emotions. it amazes me they don't teach emotions in school.
try and just feel anger without letting it control you, the feeling will pass.