def process_pairings(pairings_file):
    """ Reads in pairings from the comma-delimited pairings file and creates 
        a list of lists """

    pairings = []
    with open(pairings_file, 'r') as f:
        for group in f:
            group = group.strip().split(',')
            pairings.append(group)
    return pairings