I would create "swarms" of small drones. The swarms would each be on a different frequency. They would attack in waves from different launch points on preprogrammed routes.
An individual drone would carry a grenade size payload. Some would be fragmentation some thermite and CS gas fused for proxmity, impact and delayed.
An individual drone would carry a grenade size payload. Some would be fragmentation some thermite and CS gas fused for proxmity, impact and delayed.