Hi,

must be create a new module inherit of res.partner for add a onchange() methode to category_id field.

in your file.xml

<field name="category_id" 
                        on_change="onchange_category(category_id)"
                        widget="many2many_tags" placeholder="Tags..."/>

in your file.py

 def onchange_category(self, cr, uid, ids, value):              
       for category_id  in value[0][2]  : 
           category_name = self.pool.get('res.partner.category').browse(cr, uid, category_id).name
           if category_name == 'blind dropship' :
               return {'value':{'customer':False,'supplier':False,'opt_out':True}}
               break
       return {}

Thank you.