Yeah, this is a way to organize different web forms for different users. But unfortunately it won't help on my issue.
My problem is the number of web forms I'll have to modify to restrict ALL fields of Configuration Item form. At first, I should modify cmdb_detail.htmpl for common fields. But then, I'll have to modify the htmpl of each tab, and for each family, modify its attribute tab.
For example: nr_cmdb_har_serx_tab.htmpl for Hardware.Server family classes, nr_cmdb_net_roux_tab.htmpl for Network.Router family classes, nr_cmdb_tel_cirx_tab.htmpl for Telecom.Circuit family classes, and so on...