Splitting multi window imported video

we are currently working on a theatre project which requires video project.

Another theatre group previously performed the same show and have kindly provided us with the videos they generated , which is really helpful but there is one small problem.

In their videos they effectively combined three video streams side by side which unfortunately doesn't work for us. What we need to do is to recreated the three original streams so we can edit them as required.

Does anyone know if it is possible to split them in IMovie ?

Thanks ( fingers crossed )