Force BE 2014 to use specific scratch tape in an auto loader

Hello

We have an MSL 4048 auto loader with 2x LTO 5 drives

I want to set up a backup job but to force that job to use specific scratch tapes, which are LTO 4 tapes.

As the person that will get these tapes will restore them with an LTO 4 tape

assuming that in the scratch media i got both LTO 4 and LTO 5 tapes,

How can i force BE to load a LTO 4 tape from the scratch media pool?

THANKS