Needs review
Source: Encyclopedia Arcane: Illusionism

Description: You can maintain multiple independent spells at the same time.

Prerequisites:

You gain the ability to concentrate on more than one spell at a time and to cast other spells while maintaining your concentration on those spells that need it.

Table 1-1: Concentration DC

Effect	DC
Maintain Concentration on multiple spells as standard action	10+ total level of spells you're concentrating on
Maintain concentration as move equivalent action	10 + total levels of spells you're concentrating on + the number of rounds the character has maintained concentration as a move equivalent action
Maintain concentration while casting another spell	10 + the level of the spell you're casting + the total levels of spells being currently concentrated on