To be perfectly honest, the proper etiquette would have been not to apply for multiple aways for the same month until you heard yes/no from the other programs. The ones you have to cancel on will probably remember it...sorry, but its the truth. Getting aways is stressful and I know you want to make a good impression; if I were you, I'd try to schedule at least one of the other two programs on another date. Hope this helps...
