Blessing of Eating Together & Saying Bismillaah at the Beginning
A man said: ‘O Messenger of Allaah we eat but we do not feel satisfied.
The Messenger of Allaah (sallahAllaahu alayhi wasallam) said:
“Perhaps you eat separately from one another; gather together at your food and mention the name of Allaah The Exalted upon it so that your food will be blessed.” 
1. Silsilah as-Saheeha: 664