Complex sentence: Three groups of smugglers had gathered; one to unload and transport the cargo and two groups of "Batmen", to protect the first, they were spotted by a few local blockade men, as the main blockade force had been lured away by the smugglers.
Split into simpler sentences: Three groups of smugglers had gathered: one to unload and transport the cargo and two groups of "Batmen", to protect the first. They were spotted by a few local blockade men, as the main blockade force had been lured away by the smugglers.