ability to recognize a guest nick a registered nick

[profeta43]

hello, I have a chat phpfreechat version 1.3 integrated in my phpbb3 forum, everything works perfectly, the only problem is that logging in as a guest you can also use a nik registered phpbb3 on the board, and this is not good because anyone could impersonate c to a user registrato.volevo know if wax can pemmettere recognition to nick guests maybe assigning a specific color to the nick or better to add an asterisk to nick ospite.spero have been clear and to receive a response.
thanks in advance