CRM 7.0 Web UI - Authorization for Mail Forms

Hello Gurus,I

I have 2 companies on the same SAP CRM,  each one with his own Marketing´s department, then I need segregate the mail forms.

I´ve executed the form creation with activated trace (ST01) and I could identify just a authorization objetc - CRM_IM_ML (Authorization Object for Mail Forms), but it has only Activity field, that´s not enough for the requirement.

Please,  any ideas , suggestions how can I do that? We are implementing CRM 7.0 Web UI.

Thanks in advance,

Cristiane