Redundancy

The company are making 9 people redundant in the same department. 4 of those people qualify for redundancy after working between 9 - 11 years with the company. Everyone has been given a 9 week notice period including the four that have worked for the company for a number of years the other 5 have worked for the company for only 1/2 years. Is this fair? Could the four leave the company after one week and still get their notice payment or even work the 9 weeks then request a further notice payment in recognition of service?