Can acros sting each other?

yah they have the capacity to sting eachother. Acroporas usually wage pretty weak and local wars, typically there's not much fall out and they just go on indefinately battleing for millimeters of dominance. Usually a ridge builds up right around where they're fighting, and it waxes and wanes with new growth and cyano cycles. I've also found tho that some species of acropora seem to be histocompatible with eachother and do not wage battle. I have a bali green slimer and an ORA miami orchid (both A. youngie (presumably, lets not get into to many nitty gritty details on taxonomy though!)). These two staghorn acros that I have are resting on one another without so much as a sliming dispute!

In short, yah they will probably be fine, the portions of the colony that aren't touching eachother will hardly know the difference.