Can I block kids access for specific hours for specific websites?

I don't mind if my kids are on certain websites (like facebook, for example), however I do NOT want them to have access to that website at all times of the day.
I would like to block access to that site only during the time of day that they are supposed to be doing their homework (5 to 8 pm).

I cannot figure out a way to block out certain hours on certain websites without blocking access to the website entirely.

Does anyone know if it is possible to block out access at certain times of the day without blocking access to a website entirely?

Thank you.

 

I use my routers firewall for this. Draytek works well, Billion less so.

 

Hello,

This is not available in the current version of ESET Smart Security, but I have passed your product enhancement request onto ESET's developers for consideration in a future release of the software.

Regards,

Aryeh Goretsky