Restrict taxonomy terms when users edit content?
Taxonomy Access Control will let you set up the permissions at the term level. 


  Access control for user roles based on taxonomy categories
  (vocabulary, terms).
  
  
  Automatically controls access to nodes (based on their taxonomy
  terms). 
  Configuration page for each user role. 
  Three node access permission types: View, Update, Delete. 
  Two term access types: View tag, Add tag.