Active clients display availability

[PaAn]

Hi,

I have a bunch of clients that are in active mode behind various firewalls. I'd like zabbix to display online/offline status if the client hasn't sent anything in 5min or more.
For instance if the ping average is above 140ms for longer than 5min, the client is considered to be offline and i can get a online/offline value for a graph.

It doesn't need to be show up on host availability, but can. I just need to know a estimate how many clients are online or sending data to zabbix at a time and display the value in a graph.

[PaAn]

If this can't be done from the UI. Would it be possible to get a list of host with no data for the last xx minutes using the API. I found a similar question about this from 2013. Is there a simpler way then to poll the database directly?

https://www.zabbix.com/forum/zabbix-cookbook/31953-get-list-of-items-with-no-info-for-more-than-x-minutes

I have suspect I'm approaching this problem wrong.
Any ideas are appreciated