I think we discussed a bit of us doing this in PM with you... we are finding it very helpful to develop communication with those parts in non-triggered times. We work on inviting internal conversation when we are feeling calm and peaceful. Our T talks "through" to some parts, not inviting them out but inviting them to listen.
I don't have much time to elaborate right now but we are finding the key thing for us seems to be inviting connection conversation curiosity and collaboration with different parts when we are not triggered. Once connections have been established we seem to be able to cope and manage much better when unexpected triggers occur (once we have developed a connection with those parts that deal with that specific situation or trigger).
We do this slowly, in therapy and at home, and just work with one part at a time.