Constrain Tablix width in SSRS

Question

(SSRS 2008, using Report Builder 2.0 for design)

Hi Folks,

I have a tablix that has column groups. Since the values in columns may be different lengths (AND there are a variable number of values to group on), the width of the tablix is hard to predict. What I'd like it to do is to expand to take up as much of its parent (a rectangle) as possible, but for that parent (the rect) to NOT grow (in width) beyond the page width. There appears to be no "Can Grow" setting for the rectangle.

So my goal is to avoid horizontal page breaks caused by tablix growth, and at the same time to allow the tablix columns to adjust their widths optimally in the space available. Sounds a bit "pie in the sky". Do you think it's possible?

Thank you, Bill Dawson