How can I have friends for dinner without always including my Mom with dementia?

She just stares and asks the same thing over and over? I'd love to entertain occasional or even just enjoy a neighbor stopping by for a visit without feeling constantly intruded in on by my mom. I'm wondering if some of you may have some "tried and true" strategies that work? It seems as though those secret strategies are often the way I survive many situations each day as a weary caregiver. Thanks!