Is there a way to have different numbers of columns on tabs / pages within a dashboard.

For example - on my current dashboard, on the first and only tab - it has three columns. If I add another tab / page - then it also has three columns. Is there any way to have a different number of columns.

For example - I would like to link to another web site, and I would like it to take up the majority of the tab / page.

Thanks,
Martin.