There is a sharepoint column permission  add-on in http://www.sharepointboost.com/permissionboost.html It can:  Assign read or edit permissions to columns Make columns non-editable or invisble in edit view or display view form Make view invisible to those who have no read permissions on columns in the view

I have set up two web parts - one is a list (source) and the other is a grouped (collapsed by default) view of a library, which includes a column with the same possible values as the source list.  I have set up a web connection so that when the selects a value from the list, it will filter the library, showing only the documents that are ...