Musescore 4 - Producing mp3s for parts

I have a choral score with 4 vocal and 4 instrumental parts. I can export mp3s of individual or multiple parts and of the whole score. Separately I can use the mixer to change the volume of specific parts which I can then hear during playback.

However for practice I need to produce mp3s where the parts have different volumes. So for example I might need part 1 at 100%, but parts 2 - 8 at only 75%. Can I achieve this with Musescore 4? Or do I have to export each part as an mp3 and then multitrack them in Audacity?

Would appreciate your advice please.

Michael