I'm also the host of my system and I use the term "frontlocked"--I can't really leave front/co-consciousness. I only see the headspace in bits and flashes, so I don't know how to help you get back there, but I do have tips on communication. For us, the best way is to record it somewhere, like, we write notes to each other on the sides of my school work or essentially "text" each other on my phone

^ I do that same thing. I have a personal Discord server that I use to communicate with everyone

We haven't got much of an inner world ourselves, just a few tiny places. Try calling their names, or writing them notes or playing songs you know will trigger them out. Communication is a skill you have to establish, not all of our alters can communicate with each other. It's like you have to build a bridge between each one, or "get their phone number" in your brain, so to speak. When other alters aren't fronting they are just basically asleep for us

Internal communication is a huge struggle for me as well. I have found that leaving a notebook and sketch pad opened in an obvious place with different types of pens/ pencils/ crayons, etc. has allowed some to communicate better. (if not to me, then at least to my therapist). I wish my parts trusted me more so that they would feel safer to communicate with me directly, but all I can do in the meantime is keep trying to assure them that I am there for them and am open to listening to anything they want me to know