OK. So it looks like the intervals are basically in hours with a maximum of 6 hours or more and activation times in minutes ranging from 0.5 to at least 5.
I plan to store the setting in the built-in EEPROM so that even if power is lost you don't need to re-connect the PC until you need to make changes.
Output 1 (a solid medium size food feeder) 120,123,240,243,360,363
Output 2 (a solid small size food feeder) 0,0,180,185,360,365
Output 3 (a liquid using a valve) 120,120.5,240,240.5,360,360.5
If it's OK to have the activation times for a single feeder to be constant I would enter those as something like:
1S:360@2,4,6 // Room 1 Solid feed, activate 360 seconds (3 Min) at hours 2, 4, and 6
2S:600@3,6 // Room 2 Solid feed, activate 600 seconds (5 Min) at hours 3 and 6
3L:30@2,4,6 // Room 3 Liquid feed, activate 30 seconds (1/2 Min) at hours 2, 4, and 6
The Arduino can easily handle six rooms with two feeders each. It would also be easy to increase the number of feedings.
Is it likely the activation times would need to change between feedings? I noticed that your examples all have the activation times constant.