trigger within sound files

I am working with sound files as stimuli. I oraly present sentences to subjects to measure ERPs after certain words. My problem is that the actual stimulus is a word in the middle of the sentence. So I want the sound file to send a trigger at the position of the target word so that I later can identify the exact onset of the stimulus within the EEG. Is this possible?
I woudl appreciate very much any sort of help. And I am sorry that I have problems to express myself in English, but I am - obviously - not native speaker. I hope I could make myself clear.

Unfortunately, this is not a capability of SuperLab.