want to make a private link between to diffirent ip's

Hi i want to share files with a user that is connected to my wlan. I have added a rule that blocks all data from 192.168.8.0/24(wlan) to 192.168.0.0/24(eth1). For security purposes i had to do that cos i was able to access and ping the computers on the 192.168.0.0./24 range. What i want to do is enable computer 192.168.8.4 to access folders on 192.168.0.16 and vise versa. It must almost be like a private link. 192.168.8.4 should only be able to ping computer 192.168.0.16 on the 192.168.0.0./24 range. But computer 192.168.0.16/24 must be able to ping any computer on the 192.168.8.0/24 range. 192.168.0.16 is the administrator computer. If anyone knows what rule will help for this then that would be greatly appreciated.

PS: Mikrotik is not allowing ping from 192.168.0.0/24 to 192.168.8.0/24 but vise versa when all firewall rules is disabled.