Remote command failed when there're multiple hosts in one trigger expression

I created a trigger where trigger expression contains different hosts. And I want to zabbix server execute some script (with contains macros like {HOST.NAME1} {HOST.NAME2}) when the trigger fires.
It works when expression contains only one host(even multiply items), but I get "Too many hosts in a trigger expression" when different hosts.
The items are in active mode.
Zabbix server v2.2.6 (revision 48483) (27 August 2014)
Can anyone tell me if I misuse the function or it's Zabbix's bug?