Instead of trying to stop the dreams I think addressing the dreams would be more effective.
Our dreams are triggered by neurons firing in our brain. We have various neural circuits that are associated with ideas and with our emotions.
If we go to bed after our brain was overloaded all day with any one certain thing, it is almost certain we will dream of it and things directly associated with it in our brain. The same goes for something that is important to us but is not being addressed. Our dreams are trying to notify us and make us aware that something should change.
A simple example: If we go to bed afraid, or if we had experienced fear during our day, our fear network will be still active when we dream. The strongest firing neurons in our brain are used to fashion our dreams. In this example, we will dream of the various things that are associated with fear (in our brain). Our dream is likely going to cause us additional fear. For some this could an attack of killer spiders. For others it could be scary zombies.
Dreams can get a bit whacky when two separate neural circuits are activated from our day when we go to sleep. If I was really stressed out and I also played alot of chess (and thought a lot about chess) I may have a really bizarre stressful dream involving giant chess pieces that I cannot move, even though it is my turn to move. Or, if I have associated stress with school exams, I may merge the idea of school exams with chess since my stress network was active and anything connected to the idea of stress, in my brain, is fair game for the dreamworld.
I believe your solution is to actually pay as close attention to the dreams as possible. They tell you very private information about yourself. Examine what you are feeling in the dream and what you are doing. Also examine what the symbols mean to you. I believe you can change your dreams when you change the things that are causing your dreams. Once they are less stressful, wierd, or not-the-norm you will tend to not even be aware that you are dreaming. When something normal happens our brain usually processes it in our subconscious stream. We aren't bothered by it. There are too many things like that going on and we would be literally crazy if we were aware of it all. When we see someone who looks dangerous and could be a threat, and he is headed our way, that is something worth getting our focus and attention for. Our conscious stream is alerted... Your dreams are ALERTING you of something.... I would try to pay attention to them.
A simple "aha" could easily stop the bothersome dreams. I actually believe the stress induced by trying to stop them could cause them to become more persistent!!!!
The key is to understand them.
Best of luck!