Complex sentence: As was typical of many Indian tribes, each band saw to its own, although with outside pressures from the Spanish, French and Americans, as well as neighboring tribes, the Pawnee began to draw closer together.
Split into simpler sentences: As was typical of many Indian tribes, each band saw to its own. In response to pressures from the Spanish, French and Americans, as well as neighboring tribes, the Pawnee began to draw closer together.