Sliding audio in multiple clips

I want to slide the audio in multiple selected clips (all clips in the montage, actually). They must remain in alignment with sample accuracy, so I can’t do them one by one. I thought that holding the Alt key down for a multiple operation might work, but then I realised that the Alt key is also used (with Ctrl) to select the slide operation. Is there a trick that could do this, or do I have to work out how to program it in the batch processor (which I’ve never used)?

Never mind - it would have been neat, but instead I inserted the same amount of silence in all the source files, which had the same effect with little trouble.