Calculated item, wildcard ?

[mcmyst]

Hello,

I am looking for a way to add different items from different hosts.

Here is the thing:
- We have hundreds of switches (Cisco and Alcatel lucent)
- We have items to get IN and OUT traffic on every interfaces

Exemple:

- HostGroup: My_group
-- Host: My_switch1
--- key1: FastEthernet1-1.ifHCInOctets
--- key2: FastEthernet1-2.ifHCInOctets
--- key3: FastEthernet1-3.ifHCInOctets
--- keyXXX: FastEthernetX-X.ifHCInOctets
-- Host: My_switch2
--- key1: FastEthernet1-1.ifHCInOctets
--- key2: FastEthernet1-2.ifHCInOctets
--- key3: FastEthernet1-3.ifHCInOctets
--- keyXXX: FastEthernetX-X.ifHCInOctets

What I would like to do is to take a group of switch (placed in a specific Hostgroup, here, My_group) and sum/add every ifHCInOctets to make a calculated item of item ifHCInOctets. I also would like to do the same for ifHCOutOctets.

So I have tried a calculated item:

grpsum["My group",%.ifHCInOctets,sum,1m]

And this:

grpsum["My group",*.ifHCInOctets,sum,1m]

But it doesn't work:

No items for key [%.ifHCInOctets] in group(s)

Do you have any idea ?

EDIT:
My problem is the same as this guy: https://emwww.zabbix.com/forum/showthread.php?p=102086 but nobody have answered him.