Formatting parts

Hey guys,

I don't know whether I am doing something wrong here or if it us the inability of MS4.
Whenever I start to format the parts weird things happen to already formatted parts. So let's say I'm already with the layout of Violin I, as soon as I go on to Violin II, the entire layout (breaks, manual adjustments etc.) of Violin I is not where I left it. Breaks, for instance, seem to be taken over from the very last part I've worked on.
And believe me, Violin I does not look well with the page breaks of the horns ...

I already have three separate files for the score, the parts and the audio ... do I now need a separate file for every part if I want formatting to be untouched?
Or is there a way to "disconnect" the parts from each other? Or do I mess up saving that file somehow?