Complex sentence: All the Houses on Carver V are avoiding any military action that could endanger the peace, so when a suspiciously well-equipped bandit force threatens Steiner territory, the House uses a quite unusual countermeasure-a mercenary team.
Split into simpler sentences: All the Houses on Carver V are avoiding any military action that could endanger the peace. A suspiciously well-equipped bandit force is threatening Steiner territory, and the House uses a quite unusual countermeasure-a mercenary team.