How to group the data in an array into similar numbers?

I am trying to group the conents of the array (prob_descend) into numbers which are similar (for example 0.4 and 0.3 into one array) and the rest into another array.

Any ideas on how i could sort the values into similar groups?

%Fano method 
clear
symbols = (1:6); %demonstrates the symbols 
prob = [.4 .3 .1 .03 0.11 0.06]; %probabilites relating to symbols
prob_descend = sort(prob, 'descend');%sorts probabilites
[m,n] = size(prob_descend)
fano_array = mat2cell(prob_descend, [1], [n/6 n/6 n/6 n/6 n/6 n/6])% seperates the array with probabilites into seprate cells 

for i = 1:n
    %calculates 
    array_new = n/2;
    fano_arr = mat2cell(prob_descend, [1], [array_new array_new]);
    [r,c] = size(fano_arr(1,2));
end

[Jan]

Why are 0.3 and 0.4 "similar"? What is the relation between your question and the shown code?