Change # of columns within a layout part?

[BAleiHi]

I want a layout with a fixed header for every page across the whole page, a leading sub-summary across the whole page, then another leading sub-summary and a body that each span two flowing columns, then a trailing sub-summary across the whole page.  From what I can tell, FM can only do the flowing two column thing in all the layout parts except the header and footer, not specific to particular layout parts.  Any chance 16 or 17 have that feature? (I'm in 14).  If not, any ideas for a workaround?  Any way to get the contents of the header and footer to vary like a sub-summary? Any other possible workarounds?  Thanks,