Grouping data in a matrx

I have a 2 column matrix with some data. The fist column represents a time index, and the second column represents data for that time index:

so I want to create a matrix that looks like the one below:

so that I can plot a scatter that looks the one below:

I have tried findgroups without success. How best can I implement that?

Thanks a lot for your assistance.

Answer 1

[KALYAN ACHARJYA]

time_data=[1 1 1 2 3 3 3 4 4];
data=[10 16 14 18 13 14 23 26 29];
time_data1=unique(time_data);
data_result=cell(1,length(time_data1));
for i=1:length(time_data1)
    idx=find(time_data==time_data1(i));
    data_result{i}=data(idx);
end
data_result

The resultant groups are saved in a cell array.

Results:

data_result =
  1×4 cell array
    [1×3 double]    [18]    [1×3 double]    [1×2 double]
>> data_result{1}
ans =
    10    16    14
>> data_result{2}
ans =
    18
>> data_result{3}
ans =
    13    14    23
>> data_result{4}
ans =
    26    29