Shared parameters for some familys of certian category but not others of same category?

[wr.marshall]

Is there a way to to control visibility for shared parameters for a category. IE if I have a 2 GM where 1 GM( "Parameter=Paper type" for a notepad) needs certain information and the 2nd does not. By applying shared parameters it is applying them to both. The second GM(A Pen - contains the "parameter=paper type") does not need these parameters and could be confusing to someone using the family for the first time. 

Forget about the argument ACAD is not Revit and different programming methods(blah, blah, blah....) but a similar case would be Blocks in CAD where I might have a dynamic block called meeting equipment containing the pen and notepad. When changing the the block to the pen, and the parameter is hidden(within the block), it would not show in the properties.

[martijn_pater]

You mean family types? You could use nested families and have different types... so a family called meeting equipment containing the (shared) pen and notepad (type parameter), as you say. The family itself has the parameters it has though. Doesn't make a lot of sense though, you should just have two families for the pen and notepad.

edit: forget the above, you just have different families. If the one needs the shared parameter you add it, for the other if it doesn't you don't add it...