Psychic Focus

Contact requires that you must maintain a form on concentration that allows the continued contact with a subject. If this concentration is broken then so is all contact. Normal activity, such as moving and Attacking, doesn’t interfere with this. The following factors can break psychic focus:

Taking Psycic Damage. Whenever you take psychic damage while you are concentrating on contact, you must make a Intelegence saving throw to maintain Contact. The DC equals 10 or half the damage you take, whichever number is higher. If you take damage from multiple sources, you make a separate saving throw for each source of damage.
Being Incapacitated or Killed. You lose Contact if you are incapacitated or if you die.
Psychic Phenomena. Some psychic phenomena require you to succeed on a Intelegence saving throw to maintain Concentration on a ability.

You can use abilities like Gird or Splinter Mind can be used to block off different sets of contacted minds to different groups to maintain focus on them separately. These additional focuses are separate and in addition to normal concentration.