Group prints at least once regardless of expression

[nash.seq]

Is there any way to not print a group even once in a report? Using null or blank as a group expression always prints the group at least once after the first page's column headers band. According to the iReport Ultimate guide for group expressions:

This is the expression that JasperReports will evaluate against each record. When
the expression changes in value, a new group is created. If this expression is
empty, it is equal to null, and since a null expression will never change in value,
the result is a single group header and a single group footer, respectively, after the
first column header and before the last column footer.

I want to be able to change the frequency of group occurence based on a GroupBy parameter (e.g. $P{groupBy1}.equals("foo")?$V{REPORT_COUNT}:null), and while I already have a solution to have two seperate tables that print conditionally based on GroupBy parameter, one for grouping, and one for not grouping by setting group header and footer height to 0, I'd rather desire to reduce number of tables I use in the report if there's a better way.