buffer() from the Signal Processing Toolbox can handle overlap.
If you are asking about timeseries objects, then the answer is that individual timeseries objects do not automatically support multiple sub-signals at all. You can extract sections of a timeseries, such as in a loop
NFFT=1000;
overlap=500;
for start_index = 1:NFFT-overlap:number_of_samples-NFFT+1
this_section = getsamples(TheTimeSeries, start_index:start_index+NFFT-1);
... do something
end
