Storing data in lots of separate variables should be avoided, read this to know why:
The simplest solution would be for you to reshape your array into a matrix and access its rows/columns:
C = cell(1,192) % your cell array M = reshape(C,8,);
then accessing the data that you require is trivial using basic MATLAB indexing:
M(1,:) % 1, 9,17,... M(2,:) % 2,10,18,... ... M(8,:) % 8,16,24,...
Note that you can easily access the data in a loop:
for k = 1:8 M(k,:) end
or split it into a cell array of cell arrays using num2cell.