Here's one way to do it:
Step 1: make a backup copy of your data so you don't lose anything.
Step 2: At the left-most column, insert 2 new columns.
Step 3: In the new column A, starting at row 1, number each row using
your favorite method (data fill, etc).
Step 4: In the new column B, in row 1, enter 0. In the following row,
enter 1. In the row after that, enter this formula: =B1 (or whatever
row holds the zero value in this column). Copy this formula down to
the last column. You should see 0,1,0,1 etc alternating through the
entire list.
Step 5: Sort all rows on column B. All the zero entries will be
grouped; all the 1 entries will be grouped.
Step 6: Move the appropriate group to a new tab.

Column A will allow you to re-sort data into its original order if for
some reason it gets out of order.