Create a new table from existing table (Using DAX Commands)

Anonymous 

It can actually be done in a far, far easier way if you have a column that specifies order in Table1 (or add an index as suggested by nandic). In my previous take, I somehow (must have been asleep) assumed you wanted a solution that would use the "Affected by" column in "Table1 (updated)". This only overcomplicates things unnecessarily

Table2 =
GENERATE (
    Table1,
    SELECTCOLUMNS (
        CALCULATETABLE (
            DISTINCT ( Table1[Store_Number] ),
            Table1[Index] < EARLIER ( Table1[Index] ),
            Table1[Slow] = "y",
            ALLEXCEPT ( Table1, Table1[IDNO] )
        ),
        "Affected by", Table1[Store_Number]
    )
)

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