Hi Sehrish, Kabeer  thanks for the tips, although I think I´m getting closer, I still can´t make it work, I went coding with method 2 (Sehrish) using it inside a computed field but several exceptions have been occurring:
field: 
'make_invisible':fields.function(get_user, string="Is Invisible", readonly=0)
XML:
<field name="make_invisible"/>
First try:
def get_user(self, cr, uid, ids, name, arg, context=None):   
    _logger.debug("This is GET_USER method ")  
    desired_group_name = self.env['res.groups'].search([('name','=','GM')])  
    is_desired_group = self.env.user.id in desired_group_name.users.ids        
    self.make_visible=is_desired_group
got: 
desired_group_name = self.env['res.groups'].search([('name','=','GM')]) 
AttributeError: 'hr.employee' object has no attribute 'env'
Second try: (try to use api.multi to avoid previous error)
@api.multi 
def get_user(self, cr, uid, ids, name, arg, context=None): 
    _logger.debug("This is GET_USER method ") 
    desired_group_name = self.env['res.groups'].search([('name','=','GM')]) 
    is_desired_group = self.env.user.id in desired_group_name.users.ids        
    self.make_visible=is_desired_group
got:
File "/opt/odoo/openerp/api.py", line 363, in old_api 
    result = method(recs, *args, **kwargs)
TypeError: get_user() takes at least 6 arguments (4 given)
Third try: (use different function definition with api.multi)
@api.multi 
def get_user(self): 
    _logger.debug("This is GET_USER method ") 
    desired_group_name = self.env['res.groups'].search([('name','=','GM')]) 
    is_desired_group = self.env.user.id in desired_group_name.users.ids        
    self.make_visible=is_desired_group
got:
File "/opt/odoo/openerp/api.py", line 709, in __new__  
    self.cr, self.uid, self.context = self.args = (cr, uid, frozendict(context)) 
ValueError: dictionary update sequence element #0 has length 1; 2 is required
Fouth try: (tried to use original function definition with pool.get instead of env)
def get_user(self, cr, uid, ids, name, arg, context=None):  
    _logger.debug("This is GET_USER method ") 
    #desired_group_name = self.env['res.groups'].search([('name','=','GM')]) 
    desired_group_name = self.pool.get('res.groups').search([('name','=','GM')]) 
    is_desired_group = self.env.user.id in desired_group_name.users.ids        
    self.make_visible=is_desired_group
got:
File "/opt/odoo/openerp/api.py", line 241, in wrapper  
    return old_api(self, *args, **kwargs) 
TypeError: search() takes at least 4 arguments (2 given)
Please help, dont know what else to do and what am I doing wrong!!!
            
Define your function like this
` def get_user (self, cr, uid, ids, name, arg, context=None):
//statement