Restrict Outlook Anywhere from Internet

Hi All,

We have Exchange 2013 Infrastructure with everything working fine.

I am trying to find a solution where I can restrict users(30% out of all) to connect to Outlook from Internet i:e Outlook Anywhere but allow them to connect when on LAN. Is there an option to rerstrict it on the basis of Active Directory Group. I tried the below however it fails to connect from Internal\LAN as well.

Set-CASMailbox –Identity John –MAPIBlockOutlookRpcHttp $True

Any help will be greatly appreciated.

Regards,

Avis