MADRID (Reuters) – Ground staff at IAG-owned Iberia airlines will stage a four-day strike at Spanish airports from Friday, forcing the cancellation of hundreds of flights, after talks between unions and the company failed at a last-ditch meeting, the airline said. Ground staff including baggage handlers are protesting against contracts signed with new providers at Spanish airports. Spain’s two main unions UGT and CCOO plan a walkout from Jan. 5 until Jan. 8, disrupting travel over the country’s traditional Epiphany holiday. A member of Iberia’s press office said Madrid airport would not be aff…