halacha - Saying kaddish when davening in a minyan that isn't your nusach

I have been to many minyanim where people are saying kaddish of a variety of nuschaot. What should one do with regards to this?

Some examples: In a sephardi minyan, should an ashkenazi person remain silent for those parts of kaddish that a sephardi person would say? Conversely should a sephardi person assert his nusach of kaddish by quickly adding the additional parts that he would say if he is in an ashkenazi minyan?

Does it make a difference that it is 'easier' for an ashkenazi person to remain silent for parts of kaddish in a sephardi minyan in comparison with a sephardi person adding extra words within an ashkenazi kaddish?

Additionally, if you are in a non-nusach-specific minyan, what is the ideal way to say kaddish with other people who are saying it with a different nusach to you?