Pause input into enabled subsystem when valid signal = 0 Simulink

My simplified Simulink model involves plotting a sine wave going through an enabled subsystem. The simulation time step is 1/(125e6) seconds and the subsystem is only enabled once every 1/(250e3) seconds using a pulse generator. When the subsystem is disabled then the input sine data is 'lost' which is why the output looks like a jagged sine wave in the picture.

I need a way to pause the input data from flowing when the subsystem is disabled so that no sine data is 'lost'. The result should look like a very spread out sine wave. A simple way to accomplish this is to make the sine wave output at a frequency of 250kHz so that it's perfectly synced with the enabled subsystem, but this is not possible for my application.

I need to use an upsample block that has an upsample factor = 125e6/250e3 = 500. This will pad out my sample with an exact amount of 0's so that no data is missed when the enable block is disabled.