Membergroup Count

[Harelin]

Fairly simple question, I think...

What code would I use to display the total membergroup count, of several groups combined?  To put it into simplest terms, I basically want to list the combined member count of the four membergroups listed in my roster (found here: http://www.evcitadel.com/ev/index.php?option=com_smf&Itemid=26&action=static&staticpage=4 ) - Triarii, Principes, Hastati, and Inactive... in the form of 'Total Member Count: x' (x currently = 100)

[Harelin]

If I can't combine the counts, by the way, I'd be content to know how to list them individually.

[Harelin]

Anyone?