creating a macro made of macro's in hobbit-alerts.cfg

Is it possible to create some macros of hosts, then bundle combinations of those smaller macros into larger ones?

Say I have 3 groups of systems:

$DB=%(db1|data1|dbase).domain.com

$MAIL=%(mail1|smtp|webmail).domain.com

$WS=%(ws1|fred|wilma).domain.com

I'd like to make 2 macros of those systems, one for critical systems, the other for everthing on my network:

$CRITICAL=%($DB|$MAIL)

$ALL=%($DB|$MAIL|$WS)

Then use only the variables $CRITICAL or $ALL as my HOST=<variable name> entry.

If this can be done, I'm having problems getting the syntax right. Any pointers?

Thanks, Tom