While Powerware and Tripplite have had this feature, APC just recently added it in their 5th generation systems.
Switched Load Management is described as
By using new APC Smart-UPS with switched outlet groups and PowerChute Business Edition 9.0, users can configure the exact sequence by which equipment shuts down and restarts so that more critical servers stay online longer. Users can also power off less critical equipment under certain conditions to conserve runtime. This increased flexibility means greater availability for mission critical equipment.
Look for this SLM in our 5gen APC units: 200v, 300v and in most of our newer Powerware (p9212v), Tripplite (to313) and Liebert Units (lp312).