Tercio Models with this special rule may only be selected as part of a Tercio (see the rules for Tercios on page 68). When a Reaction is declared for a unit with this rule that allows it to make a Shooting Attack or Move, then all units from the same Tercio that are ‘In Formation’ with the Reacting unit may also Move or make a Shooting Attack as described in the Reaction being made (all units that Move or Shoot are counted as having made a Reaction, and thus cannot make further Reactions in the same Phase, and must target the same unit with any Shooting Attacks made). A unit is ‘In Formation’ when that unit is in unit coherency and has at least one model within 3" of a model from a different unit in the same Tercio that is also in unit coherency.
