[Mystvan]

I extracted texts from Wikia about the Saudaukar.

They had a distinct combat style, which allowed them to be recognised easily.

When in close-quarter, hand-to-hand combat, if they found themselves surrounded they would group into threes and adopt a fighting stance with their backs to each other.

During the Harkonnen attack on planet Arrakis when it was under the control of House Atreides, Sardaukar troops were provided by Emperor Shaddam IV to assist the Harkonnens. Even though the Sardaukar forces were disguised in Harkonnen livery, the Atreides managed to recognize the Sardaukar by their combat style.

Source: Wikia

Their fighting style demonstrates that they trusted their respective rearguard “unguarded” or the “blind spot” to each other of the group.