Underlay possible?

I'm converting Crystal reports to RS reports. One of the reports has a group header "underlaid" with the detail rows, with the effect that it appears to actually be on the detail row, like this :

Column 1 Column 2 Column 3
-- -- --
xxxxxxx xxxxxxx xxxxx
xxxxxxx xxxxxxx
xxxxxxx xxxxxxx
xxxxxxx xxxxxxx

xxxxxxx xxxxxxx xxxxx
xxxxxxx xxxxxxx
xxxxxxx xxxxxxx
xxxxxxx xxxxxxx

Where Column 3 is a running total of Column 2.

Any thoughts on how to accomplish the same effect in RS?

I could easily put a running total in Column 3, but to have it displayed conditionally based on whether this is the first item in the group, that's what eludes me.

[765 byte] By [doubleamericano] at [2008-2-21]