Two people, one username, at the same time

Hi,

today my JahiaSite allow my users login using the same username at the same 
time.
I want to deny this possibility. 
I want to do something like that:
1) I login with user XPTO
2) Another person try login using XPTO
3) My session is blocked.

Or:
1) I login with user XPTO
2) Another person try login with XPTO
3) The second person is blocked.

There is an away to configure any of this possibilities on Jahia?

Thanks,

-- 
Márcio Ferreira
Garimpar.com <http://Garimpar.com> - Informação é tudo!!!
Tel: (13) 3216-1967 Ramal 202
Rua do Comércio 44 sala 02
Centro - Santos - SP