How can i use 2 soundfonts for different instruments?

I have 2 soundfonts in the synthesizer: 'MuseScore_General.sf3' and 'GeneralUser GS v1.471.sf2'
I have 30 Instruments. For 29 of them i want to use 'MuseScore_General.sf3', But for the last one i want to use 'GeneralUser GS v1.471.sf2' because it has an option of 'thunder' in the mixer, which i cant get in 'MuseScore_General.sf3'. I hope that makes sense.
Is it possible to do this? If so please could you give me step by step instructions as i am new to using 2 soundfonts. I've only ever just used 'MuseScore_General.sf3'
Thank you