Not sure if posting my query  here will help. But I am still giving it a try. Our family is in the process of obtaining Green Card by virtue of my sister-in-law being a US citizen. We have been already asked to pay $400 each for my family members and the Affidavit of Support is being submitte very soon. As moving all of the family memebers at once, I am thinking of sending my wife (being primary applicant) and my elder son who reaching the age of 21 very soon. And me and my younger son will join later.

Now my query is, will there be problem/complication if I and my younger son go later after sending my wife and the leder son. OR is it advisable that all of us go together to US as the first entry?