You won't be able to load them all at once but you could easily use a for-loop to process them one at a time. Something like this:
source_dir = 'path/to/source/'
dest_dir = '/path/to/dest'
source_files = dir(fullfile(source_dir, '*.xls'));
for i = 1:length(source_files)
data = xlsread(fullfile(source_dir, source_files(i).name)));
#do something with data
xlswrite(fullfile(dest_dir, source_files(i).name)));
end
