Complex sentence: The contingents from most native groups which helped the Spanish were typically very small, about fifteen me but the Pimas contributed dozens of warriors to Captain Allande during the years who fought in most if not all of the frontier expeditions.
Split into simpler sentences: The contingents from most native groups which helped the Spanish were typically very small, about fifteen me. The Pimas contributed dozens of warriors to Captain Allande during the years and fought in most if not all of the frontier expeditions.