If you mean you want to a filter an area of the clip, like a corner or the top or bottom, you cannot.
If you mean filter a period of time, for example to filter the last minute of a clip,you can add your clip again and draw in the clip handles on the side to realign the time and segments. So, instead ofone 5 minute clip you can make a 4+1 minute clip; the last minute being filtered.
