Time Limit access to [Steam, Skype, etc]?

I have a new install of OpenWrt on a R7800. Is there some form of 'nanny program' I can install to limit the access to Steam/Skype/any web site to [X] hours in a 24 hour period?

I don't want to limit access by the computer's MAC address to the internet in general, just limit access to certain sites to a [reasonable] time period by day (Sat/Sun may have larger limit).



This is a tricky thing to do. What does it mean to access a site for 3hrs? For example if at 9am I open a site that has a long story posted on it, and I sit in front of the computer and read it for 3 hours vs I immediately decide I'm not interested and walk away and play basketball, how is your router to know the difference?

What I have done with my kids is institute a byte quota per day from YouTube but it was nontrivial to do and something like steam probably wouldn't work for that.