logical indexing within groups

I have a panel data set such that N observations occur over t-time periods. I've created a unique id number for each N-observation which repeats over t-time periods. See photo for example.

Next, I'd like to extract all the individuals such that hsClass==5 & hsClass<5.

Normally a table (table name is panel1) indexing could be achieved by

rows = panel1.hsClass==5 & panel1.hsClass<5;
panel2 = panel1(rows,:);

However, this results in a table with zero rows. In my case I want the indexing to be performed over the grouping variable (G). How can this be done?

[per isakson]

See Panel Data Toolbox for MATLAB by Javier Barbero Jiménez

[Andrei Bobrov]

Please attach your data as mat file.

Answer 1

[Walter Roberson]

 [uG, ~, Gidx] = unique(panel1.G);
 group_has_a_5 = accumarray(Gidx, panel1.hsclass == 5) >= 1;
 row_mask = ismember(panel1.G, uG(group_has_a_5) );
 panel2 = panel1(row_mask,:);