Force Harmony

Control Difficulty: Difficult, modified by proximity

Sense Difficulty: Difficult, modified by relationship

Alter Difficulty: Moderate

Required Power: Life Detection, Life Sense, Projective Telepathy, Receptive Telepathy

This power can be kept “up.”

Effect: This allows several willing Jedi to manifest the power of the Light Side. As long as this power is held up, it bathes the users in the celestial illumination that is the Light Side. It can act as a shield against the powers of the Dark Side, giving an extra
5D for each Force user involved to resist the effects of powers called upon by Dark Side servants. Note that +5D may appear to be an immense bonus, but since this power must be kept up, the Jedi calling upon the power is suffering a 2D penalty simply for
calling upon this power. One can only link as many Force users as the initiator of the power has control or sense dice, whichever skill is lower. For example, if Leia used Force harmony, since her control is 5D+1 and her sense is 4D+2, she would only be able to link a total of four people (including herself). When acting as a shield against the Dark Side, if both the control and sense rolls  exceed the success roll of the Dark Side power used (if he power requires multiple skill rolls, the highest roll), then the Dark Side power is interrupted. All “up” powers are interrupted as if the user were stunned. It does not cancel out the presence of the Dark Side, but can distract its servants and make their actions more difficult.

Source: Tales of the Jedi Companion (page 62-63)