It's a 12x50 matrix in SuperStar? So it's 12 Circles?
I use the term "proxy" to mean its a model used only to place effects but not one you really want displayed in the Layout. If you created 4 independent Single String models of 50 pixels each with the first string starting on channel 1, 2nd string on channel 151, 3rd string on channel 301, and the 4th string on channel 451. Then you created a 4x50 matrix that also started on channel 1. The matrix would have 600 channels that overlap the 4 strings. Any effects you dropped on that matrix would also show up on the 4 strings. Therefore I call it a proxy model. You could also create another model that is a 200 pixel single string starting at channel 1 and any effect placed on any model would show up on all models. Does that make sense?