Build a list with emails of all HR /Events contacts in companies based in Dublin, Laois, Offaly, Westmeath , Galway regions in Ireland with over 5k employees

I am looking for a freelancer to help me build a list of HR/Events contacts in companies based in Dublin, Laois, Offaly, Westmeath, and Galway regions in Ireland with over 5k employees. The purpose of this list is marketing. Any industry/sector is fine, and I require the job title of each contact. The ideal candidate for this job would be someone with experience in data mining and lead generation. They should have excellent research skills and be able to work independently. Strong attention to detail is also required.