Sounds like you shuold be able to do it with the coax cable in the Kitchen, it has to go to the attic somewhere, where you can splice it. A cable box is the same as a sky box, and I have it done with my sky box. The video sender is a good idea though, most of the good ones have an IR recevie on them also, so you can swith channels from the kitchen using your remote. I used to have one a few years ago that did exaclty that.
5 yoyos is feck all though when you think about it, and you will be able to watch different chans in each room as apposed to being only able to watch one channel at a time with the coas or video sender solution.
Wexfordman