What do I need to add additional dish network receivers?

[btrcp2000]

This is more of a dish network question than a sage question...

I have one vip211 hooked up to the dish on the roof that was set up about two months ago, so all new equipt. There are two lines from the dish that go into what looks like a reverse splitter(?) or something on the outside wall, and then one coax line that runs through the wall to my vip211. I know I could have them come out and do everything necessary, but I would rather not have to explain the r5000 connection, not to mention the hassle of hanging around all day waiting for the dude to show.

I want at least one more box, maybe two. Do I have to pull another line through the wall, or will a multiswitch do it? What is the purpose of the two lines that become one before entering the house?

Thanks!