On MS Project, how can I set a calendar with local holiday/day off for a specifics resources located in different countries, for example, Australia and Ireland?
Each resource has his/her own calendar that is, in turn, based upon a base calendar. Create a new calendar (Project > Change Working Time, New) for each different company. Enter the holidays. Then when you create the resources, select the correct calendar from the Base Calendar drop down in the Resource Sheet view. By creating a calendar for the different national or regional holidays, you can then apply that calendar to any number of resources.