forwards item from portal

Hi All,

I am forwarding work item from portal .When i click forward, i get a pop up to select user name to whom i have to forward.

suppose i Give ' a' in search field ,all users who have 'a' in their name will be listed . I want to restrict name based on our group name in client.

Problem is- when user wants to forward item  and gives 'a' in search field ,It gives all uses with 'a' in name.Now if there are multiple users with the same name,sometime it goes to wrong user by mistake while forwarding.Please suggest where to enhance this ,any FM or method or search help.