Yao Xinmin provides far more than a regular wake-up call.
In the groups, students can share information about basic courses and help locate available seats in classrooms.
Yao, 63, has been a security guard at Central South University of Forestry and Technology in Changsha, Hunan province since 2007.
At that time, he was impressed to see students studying hard in classrooms when preparing for the national entrance examination for postgraduate studies, but he noticed some had difficulties getting up early.
So he helped a student by requiring him to send a photo after he arrived at the classroom, serving as a kind of amateur supervisor, he said. It did work, he added.