SD75 pack 1 horn changes SD70 packs 1,2 & 3 horn

[railfan26]

Hi, Im having a bit of a brain wash on how to get different horns for SD70 packs 1,2 & 3 without having the SD75 pack controlling the horn. It seems that whatever horn I use in the SD75 pack also uses it in the SD70 packs. The sd70 horn proxy in the SD70 packs is named SD70 but in the notepad its labeled SD75 pack 1 and I've tried editing it but it wont work. Any idea's guys?