Stop iCloud from Syncing iPhone

We have a Mac Mini and a Mac Book Air in the same room and need them to stay where they are. We also have an iPad and an iPhone 4s. As of right now, my phone wants to sync with them both but I myself only use the MacBook Air and my mom uses the Mac Mini. They are usually on for easy access and not having to wait for bootup so I am curious as to how I can stop my phone from syncing with them both and just the MacBook Air.

Both computers and all out devices use the same account.