For our household, one of the most basic ways of healing trauma is creating safety. And the safety has to be specific for each person/resident I would think. What is a warm comforting environment for one might be a nightmare for others. So hopefully you have resources to give each their own place. Also, interceeding in someones environment (say a child stuck in a memory or a representation of memories/trauma) should probably be taken slowly, with advice of system elders. It doesn't always work that way, but that's probably the wise way to go about it.
This goes hand and hand with building communication, at least for us. I kinda hold central and I build internal places. Doing both means sometimes I feel alot of confusion, because depending on who I'm with and who needs my attention, the inner world will shift.
Emapthic healing through trauma sharing:
Sharing the pain between one or more selves is a possible step towards healing. Apparently it's not always nesscary, but if someone you care about inside is stuck in a certain wound and both (or possibly more) are willing for the exchange one can choose to transfer a portion of that pain to oneself, feel it all the way through and let it go. That works really well in situations where the one carrying the pain/trauma is bound away from "feeling it through" and the one stepping in can feel an emotion to completion. Completion being when it wears itself out on its own, like crying. If the chunk of emotion transfered is too large, most likely a dissociation element will come into play before the emotion/trauma is completely resolved. You'll still have taken some of the fuel away. Again, where possible the rest of the system should be consolated to save on wear and tear.
Then there are external resources:
1. Introducing the body to soft touch and pleasant experiences. A kind of re-educating of the senses.
2. Any kind of light/love/energy/body work you feel genuine benefit from. Feel free to mix and match and come up with your own modalities if you are so interested. Or keep it simple and stick to one that really has positive effect. There is a lot to choose from.
3. Earthtouch (unless the whole concept of nature gives you squelches). Being with the earth. Gathering stones, lying in grass. Talking/meditating with natural objects. Being in and around water (for us the ocean is especially healing). Where possible get away from city inputs and just soak in "the Mama" as we put it. Mama Nature.