Complex sentence: The Old Cliftonian Society (OCS) is the Society for the alumni of Clifton College (both pupils and staff) and organises regular reunions at the school and publishes a regular newsletter for alumni.
Split into simpler sentences: The Old Cliftonian Society (OCS) is the society for the alumni of Clifton College-whether pupils or staff. The OCS organises regular reunions at the school and publishes a regular newsletter for alumni.