Arma 3: Module: Combat Get In
Bohemia Interactive's Combat Get In module allows you to easily set up crew behavior to a team in your missions.
When the troops reach combat mode, for example after identifying an enemy, they will climb aboard the linked vehicle.
This module doesn't have any property.
Open the editor and create the module "Group Modifiers\Combat Get In". Synchronize it with the crew group leader, and with the empty vehicle to get in.