selecting one column values based on difference between members of another column

Hi to all,
i have data like this
ASSAY MP Cm chr#
XY1723 408068 1
XY1727 463360 1
XY1708 880744 1
XY1709 900596 1
XY487 1174585 1
XY1641 1239146 1
XY1714 3057570 1
XY1721 3522443 1
my aim is to select ASSAY on every CHR# like this i have 12 chromosomes (values in column C), The criteria to select assay column is, i want to select Assay based on MP column and i want to select ASSAY after a range of every100,000 (hundred thousand, 100kb) value in MP column . For example if i select XY1723 and i want to select next memebr of assay column having MP column value should equal to 508068. How can we solve this in SAS presently i am using excel for this and it is taking lot of time. any help would be highly appreciated,
Thanks,
Genetist