wifi drops when another macbook gets connected

My wifi drops when another macbook tries to connect to the internet. I have a 2013 macbook pro, iPad, and iPhone. All of which have no problem being on wifi together. However, when someone else tries to connect to wifi with their laptop (coincidentally they have all been macbooks) it disconnects and the only way to get the wifi working again is to restart my time capsule. This is only the case with two MacBooks trying to be on the wifi together. This isn't a problem with other devices. I'm not sure about windows computers as there haven't been any that tried connecting to my wifi.