Mass Heal: Heal living and damage undead?

[Jarndey]

For a cleric/oracle that channels positive energy, and casts cure spells, I know that when you channel you must choose to heal living creatures or damage undead creatures.

1) For mass cure spells and for mass heal, does it work the same way? Does the caster choose living targets to heal OR undead targets to damage? or may he do both at the same time with one casting? (IE: level 17 cleric selects himself and 3 allies to heal as well as damaging the 8 undead creatures attacking the party)

2) If he uses mass heal to damage undead, does he need to make ranged touch attacks or just select targets to be affected within the range (no 2 may be more than 30 feet apart)

We had a discussion at our table and we made a group ruling, and I've been trying to find something that indicates one way or the other on how it is intended to work.

[Fuzzy-Wuzzy]

1) No, the caster just chooses targets, the living ones get healed and the undead ones get damaged. Caster doesn't even have to know which are which :)

2) No attack roll is called for, but they do get a Will save.