block / rewrite on domain

[wmusch Profile]

Hi,
perhaps not the right place to ask but I think it must be possible with ISAPI_Rewrite.

The situation is as followed:

We host a website [domain1]. We do have the domain name under management.
There is another site with the domain name [domain2]. This is a completely different company. In their DSN they redirect their domain2 to our domain1.

Is it possible to block domain2? Better.. is it possible to redirect domain2 to another site (in our possession)?

I'm curious if it's possible and how.
Hope to hear quickly.
with regards
Walther

NB: we tried using IIS IP Address and Domain Restrictions but that was just the opposite of what we want. Also we can block the IP in the firewall but then it's possible innocent visitors will be blocked too.