Restricting the content access to Internet users

HI All,

We are implemeting ESS and SRM functionalities in same portal.

THE problem here is to restrict the ESS access to the users who are logged in via internet.

Only SRM content needs to be accessed via internet and the INTRANET users must access the ESS features.

WE can restrict by the roles,but wen it is made public,same login page is appearing and the ESS users are logging in via internet and marking their attendance.This must not happen .

Please help on this ASAP.

Immediate and perfect soln will be awarded.

Thanks,

Mayu