how to select some rows(for example row 1 to 5 and then row select 11 to 15 from same matfile) from mat file?

I have a mat file having some data 1st column is a class name and rest are their feature vectors (for example format is like that: class featureVector).

1. i want to partition data form mat file X containing classname and feature vector for testing and training like:

 trainData= X( 1st row to 5th row;
               then 11th row to 15th row;
               and then 21th row to 25th row);

 testData=  X( 6th row to 10th row;
               then 16th row to 20th row;
               and then 26th row to 30th row);

i-e trainData (select 1. first five rows 1 to 5 and 2. then skip next 5 rows to select 11th to 15th row and 3.then again skip next 5 rows to select 21st to 25th row)

i-e testData (select 1. second five rows 6th to 10th and 2. then skip next 5 rows to select 16th to 25th rows and 3.then again skip next 5 rows to select 21st to 25th row)

how can i do that in matlab? plz help me