Using BY statement in ASReml

Hello all,
I was wondering if there was an equivalent statement to the SAS 'by'
statement. This is what I mean. I have several permuted datasets that
I have appended to each other so that the final datafile has 500
permuted sets, each distinguised by a set number i. I would like to
run ASReml for each i value (by i) such that I have 500 different
outputs.
I would appreciate any help provided.
Thanks

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Denis Fidalis Mujibi
Ph. D. Candidate
Department of Agriculture, Food and Nutritional Science
4-10 AgroForestry Centre
University of Alberta, Edmonton
T6G2P5, AB, Canada.
fmujibi_at_ualberta.ca