Third, the spell prevents bodily contact by evil summoned creatures. This causes the natural weapon attacks of such creatures to fail and the creatures to recoil if such attacks require touching the warded creature. Summoned creatures that are not evil are immune to this effect. The protection against contact by summoned creatures ends if the warded creature makes an attack against or tries to force the barrier against the blocked creature. Spell resistance can allow a creature to overcome this protection and touch the warded creature.By my reading, the spell is only broken against the one summoned evil creature you attacked, but remains in place against others. Otherwise, the spell would read "The protection against contact by summoned creatures ends if the warded creature makes an attack against or tries to force the barrier against a blocked creature."
Still, it's pretty vague. Seems like a GM's call, really.
The problem as I read it is the first half of the sentence says "the protection against contact by summoned creatures ends" and then it says "the blocked creature." It seems to say it ends against all creatures in the first half and against the creature in the second.