Here is a very basic way to accomplish this, no extra structures or anything. It works for a series of tic...[do stuff]...tocc statements. You can save the overall result with x = tocc on the last one.
Since it's pretty simple, there are some limitations. For regular toc, if you do a tic followed by several tocs in a row, each toc gives the time from the initial tic statement. If you follow a tic by more than one tocc, then tocc gets hopelessly confused. So you could not have more than one tocc in a row, which is not the intent anyway.
You can combine this with regular tic and toc, but only sometimes. tocc just looks for the most recent instance of tic, so using toc as in (tic..tocc), (tic..toc) (tic..tocc) works, but a nested one (tic..tocc), (tic..(tic..toc)..tocc) doesn't.
function ac_t = tocc
t = toc;
t = t + toc;
ac_t = t;
disp([' Total elapsed time for selected intervals is ',num2str(t),' seconds'])