A German soldier who feels personally offended can call a Vermittler, a mediator, before filing a formal complaint, if a friendly settlement seems possible. That is § 4 of the Military Complaints Regulation. The soldier chooses a fellow soldier he personally trusts. The direct superiors of either side may not mediate.
The mediator is to learn the facts in persönlichem Benehmen mit den Beteiligten, in personal contact with those involved, and to seek a settlement. Instead, the soldier can ask the other person for an Aussprache, a talk to clear the air, and the other must let him state his view. One form is ruled out entirely. Gemeinschaftliche Beschwerden sind unzulässig. Joint complaints are not allowed.