SPELL_SHAREDLIFE

Usage       : cast shared life
Accumulative: No
Duration    : Instantaneous
Level       : Level 25 cleric (current class cleric only)
Mana Usage  : 100

This spell causes the current hit points of all formation members to be
redistributed in ratio to the maximum hit points of the formation.

Each formation member's maximum hit points is converted to a percentage
of the formation's total maximum hit points. When the spell is cast,
each formation member (including the caster) gets a new current hit
point total that is the same percentage of the formation's available
hit points. Some players will gain, some will lose.

For example, if player A is at 500/1000, player B is at 250/1000, and
player C is at 1000/1000, the formation's total maximum hit points are
3000. Each player has 33% of the maximum total. The formation's total
available hit points are 1750. Each player will get 33% of the available
1750 hit points, leaving each of them with 583. Player A benefits a little,
player B a lot; player C loses hit points.

In a more realistic formation where each player has a different total
maximum hit points, those with higher maximums will get a proportionately
larger share of the available hit points.