htaccess partial masking?

[the_noob]

i am wondering if it is possible to do this, as i would have the permission of the site i wish to partially mask.

Person logs on to
www.site1.com/vip page redirects to www.mastersite.com/site1

When person authenticates on
www.mastersite.com/site1/members person still sees www.site1.com/vip/members .
Basically produce a .htaccess file that masks the " " part of
"www.mastersite.com/site1"/members/123.html
and replaces it with the " " part of
"www.site1.com/vip"/members/123.html and so on.

meaning although the person has left site1 they still see it as the domain address.

What is the code for this?

[eelixduppy]

You are not going to be able to do that unless you use iframes of some sort...

[the_noob]

Any suggestions are very welcome and needed.

eelixduppy: please elaborate.

mods: if this thread becomes in wrong section, please move.

thanks

jason