icmpping[<target>,<packets>,<interval>,<size>,<timeout>,<keymod>]
icmppingloss[<target>,<packets>,<interval>,<size>,<timeout>,<keymod>]
icmppingsec[<target>,<packets>,<interval>,<size>,<timeout>,<mode>,<keymod>]

In adding that argument to the end of the list no current usage would become broken.

Hmm... as i copied over the keys from the documentation i realized that nearly every simple check would benefit from that change?

for example: net.tcp.service[service,<ip>,<port>, <keymod>]

So it would be possible to check net.tcp.service[ftp,,45,A] on the first added interface and net.tcp.service[ftp,,45,B] on the second one. Why anyone would want that? Clustered services or internal and external addresses for example!

If this additional parameter does not have any meaning with respect to item behaviour, what will be the point in having multiple items which do the same?

The parameter just allows to have multiple items of same simple check on one host as otherwise the "key already in use" error is thrown.
And the usecase for that would be a host with multiple agent/snmp/* interfaces which should be checked. That would be crucial for example for a multi-node storage system. Node A has a IP/SNMP address to get values from and Node B too. Currently there we have to create two separate hosts - heck often i have to create three hosts. Node-A, Node-B and a combined node where i store the calculated items... ugly.

I already had a look at the source but i am not a C guy. Have to dig in a little more. Would be great if a experienced contributor would have a look at it.

From what you say I understand that <target> parameter will be different in those items and you won't have any key conflict.

No. I don't want to use macros for the items and the <target> parameter as i already configured the addresses in the interfaces. Just change the used interface for the item.
Added 3 Screens to clarify what i mean. That wouldn't work as icmpping is already in use on node a.

You can use host interface discovery and item prototype(s) with key of the sort icmpping[{#IF.CONN}] to automatically create ICMP ping items for all host interfaces you've configured.

Closing as Duplicate of ZBXNEXT-1490.