redirec lan user to just one site

hello

  1. i want to my lan user just access to https://site1.com . i test by web proxy but i could not do it.
    are you have any suggestion ?
    (try access to other site redirect to https://site1.com)

  2. if web proxy do not support https how can i do it for http://www.site2.com ?

internet <---------->modem<------->RB951<-------->LAN