Restricting URL Groups

Howdy,

I created a URL Group, and in the page area I listed two URLs. These two URLs are two of the domains in my multi-site network.

My install domain is: Miraculous.Me

The two domains I put in the Page URL area are:
Inventions.Me
Disruptions.Me

I then created a Level, and assigned the URL group to this level.

Then I assigned Member1 to this level. However, this member still has access to all the other domains in my multi-site network. The level did not succeed in blocking access to the others. The member by default seems to have access to my entire multi-site.

Then I created another URL group, and added a third domain. I created another level, this time I put the URL group into the negative area to block access. I assigned this blocked access Level to Member1 also. However, Member1 still has access to all sites in Multi-site.

Please clarify what the true functionality of the page URL section is.

Martin