I am trying to simulate the flow of 4 different MUs, called red, green, blue, and purple. The sim begins with a source loading red, green, and blue on a line (called SurfaceTreatment) and sending the purple MUs to a buffer. The SurfaceTreatment uses Method "sort" to sort the red green and blue MUs into their corresponding SingleProcs called "m_red, m_green, m_blue." Now I want to use the sensor on SurfaceTreatment to read which MU crosses it. This in turn should trigger the Buffer to send the purple MU to "m_purple" using the Method "sensor" only when the MU called "red" crosses the sensor. Unfortunately, this is not working and my knowledge of SimTalk is very limited. How do I get the buffer to realize what MU crosses the sensor and then send out the purple MU when the red MU crosses the sensor?