High Conflict Couples

I work primarily with couples, but I am still newer to the field and learning (have been seeing clients for 6 years now). I am trained in a popular couples modality and that is my default for couples. It works wonderfully well when clients are responsive to it and follow the structure/directions/interventions. I am compassionate, gentle, and affirming, but also directive and not afraid to point things out when appropriate/needed in couples work.

I am used to conflict coming up in couples sessions, and typically when it does I will step in as needed to redirect, encourage reflection, or have the couple return to specific exercises and interventions to practice different ways of communication that help foster better understanding of one another and prevent escalation of conflict.

I have a recent couple I have begun seeing and I am at a loss because they tend to spend the ENTIRE session in high conflict, and I haven't experienced this before in my couples work. I understand what they are doing in session is not necessarily bad. It gives me a very good idea of how they fight, and of where each partner is at in their ability to regulate, redirect, see their partner's point of view etc. during conflict.

This issue however is that none of my interventions seem to be working/helping, and the couple tend to immediately go back into defensiveness/derail from intervention instructions etc. When this happens I will try to encourage reflection and bring in some parts work, so they better understand the parts of themselves that are being triggered and taking over the conversation. However, their ability to understand and reflect seems limited. I'm at a loss and the sessions feel pretty terrible. I wonder if I should refer them out to a clinician who specializes in high conflict couples, but would likely have a hard time finding options for them due to their insurance limitations.

For those of you who work with couples, what do you do with high conflict ones who spend the whole session fighting and don't respond well to your interventions or prompts to reflect/go deeper? Where do you go from there? Any resources, ideas I could look into?