you will also need to adjust the hardware key (Display ID in Xibo player options -> advanced tab)
If they have the same hardware key, the will be treated as 1 display in CMS (as you already noticed)
So as described in the link in my previous reply, if you want them to be separate ie to register each one of them separately to your CMS then you’d need to edit their hardware key to be unique.
Otherwise if all of them have the same hardware key they will appear as one display on CMS.