It is important in these dynamics to realize it is in your control not to be in that role, without going into victim role yourself and hence putting the "victim' into role of persecutor.
waverider, how do you 'step out' or 'stay out' of whatever role you are uncounsciously being invited into?
It is difficult.
It is important to realize that what you are hearing is very much one sided and in truth often non of your business. If you can support whilst being careful not to validate the invalidate.
Try to help people help themselves rather than rescue them from someone else. eg Mr X said blah blah... it was really horrible. It is better to encourage them to approach Mr X to work it out rather than "That Mr X sounds horrible I would'nt put up with that you should do XYZ " in return... Useful advice rather than involvement.
If you feel yourself slipping into victim mode then discuss it with your perceived persecutor rather than looking for a rescuer.