Double-Jumping For Different Classes

[DynamiteKaitorn]

I'm working on a mod for Hexen and I want one of the character's to have the ability to jump in mid-air. Is there a way to implement that character's mid-air jump whilst keeping the other two's singular jump intact? I saw a ZDooM forum mention about a script but that script seems to only work for single-class games like Heretic or DooM/DooM2. Any tips would be highly appreciated.