How can I group into one layer all similar items? I'd like to get all of my spheres (x.003, x.004, x.005, etc...) into a group called "Sphere" (the first one in the list).



Something like that:

Cylinder
 Cylinder.001
Sphere
 Sphere.001
 Sphere.002
 Sphere.003
 Sphere.004
 Sphere.005


Can someone explain me how to order them?
If i understood the question here the answer
If you have made the single sphere as a group ok

Select the 1st sphere and hold shift and select other spheres and group.

To find group go to outliner > drop down menu select group

Unlink group the old group (i.e. made before with 1 sphere). Right click on the old group and click unlink group