Can I extract a "sub-handle" to just part of the data in a memmapfile object?

Hi, I've got a type of data file that I'm using that is structured to incorporate several different types of related data in one file. The basic structure of the file is:

header (1024 bytes, this includes the numbers of bytes for each of the folowing parts)
summaryData1
summaryData2
rawDataStream1
rawDataStream2

To give a sense of it, the raw datastreams are likely to be up to 256MB each

I'm constructing my memmapfile object like this (yes, this is part of a classdef file too):

 mapstruct = cell(nItemsToMap,3);
                % Map the results packets
                for iChan = 1:obj.nChan
                  mapstruct{iChan,1} = 'uint32';
                  mapstruct{iChan,2} = [nWords(iChan), 1];
                  mapstruct{iChan,3} = ['Chan' num2str(iChan)];
                end

                if nDRAM > 0 % There is also DRAM data embedded
                  obj.DRAM_Pts = obj.DRAM_Bytes/4;
                  nWords = obj.DRAM_Bytes/2;
                  for iBoard = 1:nDRAM
                    iChan = obj.nChan+iBoard;
                    mapstruct{iChan,1} = 'uint16';
                    mapstruct{iChan,2} = [nWords(iBoard), 1];
                    mapstruct{iChan,3} = ['DRAM' num2str(iBoard)];
                  end
                end
                % Actually map the file
                obj.hFile = memmapfile(S,...
                  'Offset', memmapStart,...
                  'Format',mapstruct  ...
                  );

So I end up with obj.hFile. If I want to access DRAM2, I can do so with obj.hFile.data.DRAM2;

What I want to know is if there is a way (without unmapping the whole file) to create a handle to the portion of the file containing just DRAM2, so that I can treat the handle as the variable itself.

Thanks, Dan