Identify maxima value from last row of matrix

Hello, I have an array element in which first four rows are identical to previous rows in allmost all cases.

Y1   m1 d1 v1   Y2   m2 d2 v2
1970 2 21 0.982  1970 2 25 1030 1030
1970 2 21 0.982  1970 2 26 1030 1030
1971 1 24 0.5612 1971 1 29 356 356
1971 1 24 0.5612 1971 1 30 371 371
1972 8 18 0.3766 1972 8 19 445 445
1972 8 18 0.3766 1972 8 20 441 441
1973 3 2 0.29839 1973 3 7 332 332
1973 3 2 0.29839 1973 3 8 335 335
.................................
.................................
1987 1 5 1.25 1986 12 31 967 967
1987 1 5 1.25 1987 1 3 1060 1060

The first four column shows year, month, day and value. The last four represent another set of year, month, day and value. From the last four column I have to check their day of occurrence. If the event occurs within next three days, I should chose the last four rows with largest value. If they doesn't occur within +/-3 days then keep all rows. The desired output:

1970 2 21 0.982 1970 2 25 1030 1030
1971 1 24 0.561 1971 1 30 371 371 
1972 8 18 0.376 1972 8 19 445 445
1973 3 2  0.298 1973 3 8 335 335
1987 1 5  1.25   1987 1 3 1060 1060

Will anybody help me to clean up the matrix following above rule? Thanks

[dpb]

Well, would give it a shot if could follow the explanation... :)

I'm cornfoozed between 'row' and 'column' here; looks like you've mixed up which you're referring to.

But, first, is "the event occurs within next three days" the time difference between the first set of four on a record or between subsequent records of the first set of times or what, specifically?

Then the "chose [sic] the last four rows with largest value" is that really "rows" or " the row with the larger value of the RH data value (which would be one from the last four columns for the given row)"?