No—practically speaking, a triple exposure on film cannot be separated back into three original images.

With film, multiple exposures are recorded together on the same piece of emulsion, so the individual image data is combined rather than stored separately. Once that happens, there’s no reliable reference for reconstructing each exposure on its own.

In this case it’s even less recoverable because Kodachrome 25 is slide film, which has limited exposure latitude. A triple exposure adds roughly 1.5 stops, so bright areas may be blown out completely, meaning there may be no image information left there at all.

While advanced computational imaging can sometimes estimate overlapping content in special cases, that’s not a practical or dependable option for a heavily overexposed slide frame.

Your best option is to preserve and digitize the triple exposure as-is. It may have documentary and artistic value precisely because it reflects both the eruption and the camera mishap at that moment.