In most of the builds of Shadow Of Chernobyl, there was a feature that would allow the player to form a squad. You can easily find them in Build 2205. The lines used were not completed, they appeared as:
companion_hire_dialog - This will "hire" the NPC you want in your squad.
companion_management_dialog - This is probably for movement formation and others.
companion_release_dialog - This will disband the squad that the player has made.
The system can be re-activated with the help of 3rd party modification tools.
Call Of Pripyat Edit
The system re-appears in CoP. It is used during the trip to Pripyat, so that the A.I. of the team members follow the player where ever he goes, but not into hazards.