Complex sentence: A micromanager may set unreachable standards that he then invokes as grounds for termination of those employees; these standards may be either specific to certain employees or generally applicable but selectively enforced only against particular employees.
Split into simpler sentences: A micromanager may set unreachable standards later invoked as grounds for termination of those employees. These standards may be either specific to certain employees or generally applicable but selectively enforced only against particular employees.