Go for it... Some companies have a no OH's policy (I've seen a couple having a 'domestic' in an office - embarrassing for everyone!) but most just prefer OH's not to work together so if you're not working on the same site or the same team it's unlikely to be a problem. Where I work one of the bosses has his wife working in his team but they're entirely professional about it, it's just a pain for the staff for a few weeks a year when both senior members of the team are on holiday at the same time!