One possible solution:

Table --> Summary: Group by X

This will result in a table of X and frequency of each value of X. This table will be linked to the original table.

In the summary table, "Select Where" X < 5. This will highlight all the rows where X < 5 on the summary table AND the original table. Now you can Row --> Exclude, Row --> Hide, on the summary table, and that will reflect on the original table, too.

Hope that helps.