Hi Illudere,
Sounds very interesting...my only pause was trying to imagine you in a mutual mirroring or time-swapping kind of communication with a four year old, and the focus being on her "popping her issues". Sounds maybe a little overwhelming for her, if one wants her to just be a relaxed, natural child. And you don't want her to be "parentified" -- feeling responsible for doing these exercises "right" so Mommy can be okay now. (I mention parentification because I was guilty of it without knowing it--treating my child too much as my equal, not enough as the little one. Hindsight's horrible.)
But as far as YOU getting to release your feelings in a safe space, and be heard, it sounds as though you've done a wonderful job of taking your anger issues seriously and taking steps to get some help and practice that will let YOU rule your mind, rather than just your emotions ruling it. I am very impressed with that and it's also the sign of a loving parent...one who will not avoid the difficult thing of accountability. Bravo.
My vote would be for pretty mainstream anger management and parenting classes (something recommended by a local mental health organization), simply because there's so much research and practice and development behind them. But maybe Hand in Hand is an organization that isn't radical or experimental. I am allergic to forms of therapy and healing that involve a whole new set of special "insider" jargon. And also worry about gestalt types of techniques in unskilled hands.
All that said, I'll suggest to you anyway a group I have briefly participated in, even though I don't feel entirely comfortable with them. Because I know some wonderful people who love it, and do well with it, and are healthy members of a positive community. It's called RC, or re-evaluation counseling, or co-counseling. Personally, I am completely comfortable saying it has cultish origins and some of its theories are hogwash. But if you can literally tell yourself, I do NOT have to swallow all this organization's theory or jargon to benefit from the human experience I can have within the group--I recommend it simply for the "sessions" -- which involve deep expression of emotion in deep safety, and equal time sharing. It would give you that space. (Just don't go whole-hog to every single workshop, weekend, etc., etc, which they have no limit to. Bring your adult mind with you, cherish your skepticism, but be open to the people.)
I would definitely not recommend involving your child, but it would be a safe place for you to be heard and held. They're not afraid of anger. Or noise. Or snot.
And the more you release somewhere else, the less your child will have to deal with (even if she swallows it).
with love,
Hops