Time Capsule Limit Number of Users

I have a weird thing going on.. I live in a home with 3 macs 3 iphones and a ipad. Our router is an Time Capsule. The weirdest thing happens though. At a given time it seems like only some of the computers can get internet. They all can connect to time capsule, but it is broadcasting an actually internet signal to only some of the devices. Which ones get the signal is totally random to. Does anyone have an idea of what's going on???

 

I wasn't aware you could change this... where is this setting?
Thanks!