Re: To segregate or not?
Don't do or say anything. Let the guests decide and go with the flow. If they end up sitting together then so be it. If MIL asks, tell her 'mehmaan khud he ghul mil gaye haiN, ab kya kiaa jaasakta hay'
But I like PD's idea too. Make sure you don't give her a mosquito repellent. She will need company.