It is possible to join 2 or more pieces of strut either in a linear fashion, or with a bend, tee, or cross type connection if you need to.
The E922J is a linear channel/strut joiner, used to join 2 lengths of strut together. It comes in either an internal (E922JINT) or external (E922JEXT) style and works with all 41x41mm steel or aluminium strut. For 41mm wide by 21mm high strut such as the E3300 or E4400 channels use the E422J to join 2 straight lengths.
If you want to create a network of strut and perhaps create a 90° bend, a tee or a cross, there are suitable joiners available. The E922L creates a bend, and an E922T or E922X create a tee or cross type connection respectively between multiple lengths of strut.
You always need to use 4 channel nuts and countersunk set screws when installing channel joiners. Joiners are available in Hot Dip Galvanised or Zinc Plated steel as standard.