Bus journey gets more comfortable in large groups because you spend your time in talking to your known ones. Hence if possible try to get people along with you during bus journey.
Get cell number of the bus conductor. In case you miss something in the bus then you can reach the conductor and ask him to keep your belonging with him.
In case your family members have not got adjacent seats during automatic seat assignment then make a humble request to other travellers and try for seat exchange so that all of you can sit together.