Adding glissandi to rests

I have a piece of music I am transferring from a paper score to Muse Score so that I can print the individual parts for my brass band.

In one section there is a glissando to a rest. Here it says glissandi have to be placed from a start note to an end note.

How do I write the notation so that the players know to drop off of their notes over a whole beat?

I hope this makes sense.