Can i use 2 ups at once

[shetvm]

Hello,
friends, i have two ups can i use both,,
first one i connect main power, and second one i connect two first ups and pc connect two second one,,,,,,,, can i do this if any one know about this please guide me,,,, thanks for all advice

 

[prototype18]

Well i have 2 UPS using right now. I have PC and Modem to 1 and Monitor and Speakers to the other.