Divided Attention allows a spell caster to hold Concentration on a spell and cast a second spell requiring Concentration, then through the talents learned in this Feat to hold both spells as if they were one active Concentration-required spell.
When a spell requiring Concentration is cast while already concentrating on a current active spell that also requires Concentration, the caster must roll a Charisma Saving throw versus DC 6 plus 1 per casting-level of the higher level spell to be held in Concentration. Success allows the second spell to become active using the same Concentration act that held the first spell active. Failure and the second spell fails, the first spell immediately ends as well.
Only two spells may be held at once, attempting a third spell ends both spells currently held in Concentration and the third spell takes over the active Concentration. One spell held in Concentration may be dropped at will to make it possible to use this Feat again.
Once both spells are in the act of Concentration, normal rules for breaking Concentration apply, the two spells are literally one for the purpose of holding a spell through damage. Otherwise, spell durations remain separate as per each spell in use by this Feat. If a Concentration saving throw is subsequently failed, both held spells end together.