I bought a book about angels (Discovering Angels, by Christine Astel), and it has several suggestions for getting them on your side with particular problems. Anyway, I tried this one, and it has helped create a distance between myself and the beloved toxic ones. I am a very visual person, and I can use the imagery it contains to maintain emotional distance.
So, for anyone who would like to try it, here is my version, which is very close to the original, but changed a bit (Michael is traditionally described as a beautiful young man, usually in Greek or Roman style armour and carrying a sword):
1 Sit comfortably in your meditational space, in whatever way feels safe to you.
2 Invite the archangel Michael to come close to you, and visualise him drawing near you.
3 Picture the person or people who you feel are holding you back.
4 Visualise a large figure of eight made from rope, surrounded by golden light. Place the person(s) in one loop and yourself in the other, at a comfortable distance. If it helps, Visualise supportive loved ones in your loop protecting you, with you in the centre.
5 Now see Michael's sword cutting through the intersection of the figure of eight. Watch the rope as it frays, thread by thread.
6 Wish the person(s) in the other loop well on their path, and thank them for allowing you the freedom to continue along your own path unhindered. Watch as it moves away from you, but you stay still and centred.
7 Thank the archangel Michael for his help, and then sit quietly in the presence of your guardian angel for a while. Gradually bring your attention back to your surroundings.