There are several sub-nuclear options and then there is the nuclear option [not that it carries any particular weight.]
In reverse order:
3. Discuss the issue with the chair and explain that this behaviour is inappropriate, causing distress and disrupting working relationships / productivity. Request chair to monitor and take charge. Informal attempt at resolution.
2. Check your standing orders - there ought to be something along the lines of "...only one person may speak at a time and that person will be called by the chair to speak..." If that is the case then whenever interrupted you could stand up, in a bold voice raise a point of order [which should be heard immediately and be considered by the chair] This would publicly humiliate the subject and raise a minuted action. Semi formal attempt at resolution.
1. If 3 & 2 don't hit the spot, record all occasions of perceived aggressive or inappropriate behaviour and submit a conduct complaint. Formal procedure.
Be confident! Be well informed! Stand by your convictions!
PS - like your login name. Stand by it