Jaspersoft Studio 6.3.1 - Group multiple detail bands

Hi,

I would like to know how can I print multiple detail bands (all containing subreports) on one page? I have a problem because every subreport has different number of records according to users for which I'm printing reports. So when a user has smaller number of records, space is left on bottom of the page and first detail (that was supposed to be on second page, for second user) fits there on the first page, so it's all messed up.

I hope you understood me. I would really apreciate some help. 
​Thank you