Fingbox Default No Internet Access - Un-pause for specified time

In my fingbox network, I have several devices that I want to default to no internet access and be able to un-pause for a limited time (i.e. 30 minutes).   
One example is an old iPad that I let the kids use as a Kindle reader.  I don't want them using it for browsing the internet except for short periods to download new books.  Under the current system, when I un-pause the internet, I need to remember to re-pause it.
The current fingbox app allows to pause a device for a time (i.e. 30 minutes).  I'd like to do the reverse.  I'd like to un-pause the device for a short period and then have it automatically re-pause the internet.