Can a character choose the Rune domain ability "Blast Rune" with Domain Strike...? Technically speaking the Rune does only affect one creature.
Rune Domain
Blast Rune (Sp) : As a standard action, you can create a blast rune in any adjacent square. Any creature entering this square takes 1d6 points of damage + 1 point for every two cleric levels you possess. This rune deals either acid, cold, electricity, or fire damage, decided when you create the rune. The rune is invisible and lasts a number of rounds equal to your cleric level or until discharged. You cannot create a blast rune in a square occupied by another creature. This rune counts as a 1st-level spell for the purposes of dispelling. It can be discovered with a DC 26 Perception skill check and disarmed with a DC 26 Disable Device skill check. You can use this ability a number of times per day equal to 3 + your Wisdom modifier.
Domain Strike
Benefit: When you gain this feat, choose one domain-granted power that you can use to affect no more than one opponent. If you make a successful unarmed strike against an opponent, in addition to dealing your unarmed strike damage, you can use a swift action to deliver the effects of the chosen granted power to that opponent. Doing so provokes no attacks of opportunity.
