Applying for extension separately or together?

[Nikanu]

My parents arrived in the US a month apart and so their I-94s have expiry dates of March 7th 2011 and April 2nd 2011. I would like to apply for visitor visa extension for both of them but can I do it together end of January (5 weeks before expiration of March 7th date) or will it be better to apply separately a month apart in order to stay within the 4-6 weeks of I-94 expiry?
Please advise. Thank you.

[kabkaba]

Both of them will need to file separate I-539, they can be filed on the same day in same envelopes.

[ramabalaji]

You can do it together. Plase check Part 2.2 of the I 539 and also you need to fill Suppliment 3 when more than 1 person is included in the form.