Can books that are side loaded to a Kobo be synced on several devices?

I have several devices. Some for home and some for work. I carry an iPhone with me all the time and I have an iPad that I use at home. At work I have a Samsung Galaxy and I also use it for travel. I have iBooks on both of my Apple devices and Kobo and Kindle on all devices. Most books I have are in epub format so if I want to read the books across the iPad and iPhone that is okay. I can have it on all devices if I convert them to mobi files and use on the Kindle but that is a good bit of work. I have sideloaded to Kobo a few times but I cannot get the books to sync across all my devices with Kobo. Does anyone know if this is possible? And if it is, how do I do it?