make text or paragraph visible/invisible in word document

hi,

I have to make some selected paragraph invisible to some individuals (not all)in microsoft word. i tried with writting macros but the solution fails as soon as i press show/hide button.
Can any thing be done so that a logic can be written with the opening of the document itself. And also necessary tool buttons are disabled for paricular users (not all).
Also it may be that if para1 is invisible to user1 and para2 is visible to him. then para2 is invivisble to user2 and para1 is visible to hm.