Trigger set check depending on host

[jmw]

i've a trigger in a template with a check like this:
{linuxhosts:vfs.fs.size[/home,pfree].last(0)}<6

but for some host i would like to use another value.
is it possible to use a macro for this kind of work?
so that i can set in the template {linuxhosts:vfs.fs.size[/home,pfree].last(0)} < HOST'S CONFIGURED VALUE

thanks in advance for any reply...