Hey!
It's K. here. After Cat replied she got a bit worried that she had scared you by indicating that there might be parts inside who were angry with you (and I think she also perhaps felt she had got 'out of her depth' in adult conversation) so she has asked me to come and say something to 'fix it'!
I'm not sure if I can do that (or if anything really needs fixing!) but firstly, I do think every system is different. There was a lot of hostility between different parts in our system, but of course that doesn't mean there is/will be in yours. If it does turn out that there is, that also doesn't mean things can't be repaired over time - as an example, the relationships in our system have changed hugely as our understanding of each other has grown, and things are (mostly) much more harmonious now. It sounds like you are doing a good job of being open to communication and hearing what others might need. It took me a long while to get to that point, so kudos!
(But just to defend myself a little bit! I would like to point out that I don't think I ever exactly blamed other parts for the trauma they had suffered. It was more of a case of not-particularly-conscious identification with those that had harmed us. This meant that as a child I believed that the harmful actions of the people taking care of us must have been correct, and any 'negative' feelings and responses we had to those people must have been 'bad'. Other parts tended to hold these more difficult feelings, and so my attitude was quite hostile towards those parts. I'm very sad about that now and I recognise that it felt like blame to the other parts. I also understand though that I was 'doing my job' in the system as much as everyone else, and it was necessary to keep the negative feelings and responses away from my 'hosting role', even if it meant hostility towards other parts, in order to prevent further trauma and preserve attachment to caregivers. We all just did the best we could with the resources we had at the time...)
I hear the difficulty in trying to reach out to parts that you can't communicate with and who you may not even know exist. It's really tricky. It might be worth trying to send out a sort of general message that you're available and ready to communicate, and waiting to hear what comes back (in images, feelings, dreams, as well as anything more concrete), or asking a part that you do have some communication with to send a message to less known parts that you're ready when they are. I get the sense that you may well have already done that though, and I also think that it's really ok to take this slowly and gently. A thing I've come to understand/accept is that the system as a whole seems to have a lot more wisdom than I do individually, and changes tend to happen when the time is right (I'm constantly amazed by this!). Even now when we're in situation the system deems to be high risk (such as contact with our family), the other parts seem to disappear and I am not able to communicate with them at all, even though I might want to. This is one of the ways that our system maintains safety. So I think it's likely you can trust that communication will develop at the right time and in the right way for your system.
Also, Morwan - this is a great tip about the Zlibrary! I love Janina Fisher and have been wanting to read her books, but it's expensive... I will definitely give that a try too!
K.