How can I deal spesific value and add constraint?

I have matrix T

 T =[1     3
     2     1
     3     1
     4     4
     5     1
     6     1
     7     1
     8     1
     9     1
    10     1
    11     1
    12     1
    13     1
    14     3
    15     1
    16     1
    17     1
    18     1
    19     1
    20     1];

I found first column values that have zero in second column with this code

idx = find( T( :, 2 ) == 1 )

idx =

     2
     3
     5
     6
     7
     8
     9
    10
    11
    12
    13
    15
    16
    17
    18
    19
    20

After this point I want to add constraint. This constraint must find equivalent of idx's result(2,3,5,6,7,8,9,10....) in Y1 and I want summation of these Y1 values smaller than 20.

Y1=[0  12  0  0  3  1  3  1  1  1  9  0  1  0  0  10  12  1  2  3];

And then for remainder idx values, code must do same thing with Y2

Y2=[0  57  0  0  0  0  11  1  1  1  45  0  1  0  4  48  59  1  7  13];

Answer 1

[Andrei Bobrov]

    Т = [1 3
        2 1
        3 1
        4 4
        5 1
        6 1
        7 1
        8 1
        9 1
       10 1
       11 1
       12 1
       13 1
       14 3
       15 1
       16 1
       17 1
       18 1
       19 1
       20 1];
  Y1=[0  12  0  0  3  1  3  1  1...
    1  9  0  1  0  0  10  12  1  2  3]';
  Y2=[0  57  0  0  0  0  11  1  1...
    1  45  0  1  0  4  48  59  1  7  13]';

t = T(:,2) == 1;
out1 = sum(Y1(t & Y1 < 20))
out2 = sum(Y2(t & Y2 < 20))