In that case I would rather do the following:
Create an IP list under ip/firewall/addresslists which contain all the clients you wish to control's source IP's.
Then create a firewall rule which drops that addresslist (if the firewall rule is on, those IP's are blocked, if firewall rule is disabled, those IP's are not blocked)
Then create one script to only enable that firewall rule
Create another script to disable that firewall rule
现在创建一个时间表运行启用脚本a certain time,
and another schedule to run the DISABLE script at another time
If you need help writing those scripts, pop us a message
G