Identifying Specific Time Segments in Excel

I have 10,000 rows of data in Excel and the first column is the time of a data recording (hh:mm:ss). I want to filter/extract (in the front end) only the rows where the readings are at least six consecutive seconds - these are signal strength recordings and I only consider readings of at least six consecutive seconds to be valid for my purposes. I would only want to extract the rows in green in the attached image. Separate ask - what if I wanted segments of only six to eight seconds? Thanks!