Help needed blocking some videos

[AylmerQc]

I was going through some Google videos last night, as we do on occasion with the kids around for a laugh. This time I was on my own and lo and behold, this one short video had very explicit sex, I clicked the following one and it was similar in content, so was the next. Any ways (software wise) of blocking these videos without blocking all of Google Video? I set my dsl gateways Parental controls to block porn,spam and spyware sites but somehow these get trhough...