Umm... In theory atleast it should be doable. Hotkeynet does not care that they're not the same game, so all you'd really need to do is make your LoL keys to send the actual keypress to LoL and cycle through some keys for your WoWs. NOTE: I do not know what kind of cheat detection and whatnot LoL runs, so I have absolutely no idea if you'll get flagged for having Hotkeynet pass on the keystrokes to the game client. I doubt it, but it's worth mentioning.

Using this Khavotar's post, we can kinda get an idea of how one might set this up. So we could first set up a cycle for some keys to be spammed:


Code:
<Hotkey F9>
    <Toggle>    
    <SendLabel w1, w2>
            <Key 1>
            <Cancel>
    <Toggle>    
    <SendLabel w1, w2>
            <Key 2>
            <Cancel>
    <Toggle>    
    <SendLabel w1, w2>
            <Key 3>
            <Cancel>
    <Toggle>    
    <SendLabel w1, w2>
            <Key 4>
            <Cancel>
    <SendLabel w1, w2>
            <Key 5>
            <Cancel>
And then we define our hotkeys to call up that rotation for w1 and w2, while simply sending the triggering key press to our LoL1

Code:
<Hotkey scrollLockOn A-Z, 0-9, Plus, Minus, F1-F12 except W, A, S, D>
    <Cancel>
    <SendLabel w1, w2>
        <DoHotkey Hotkey F9>
    <SendLabel LoL1>
        <Key %Trigger%>
I've not used Hotkeynet in a looooong while, but if I am correct, this would mean that with Scroll Lock on, your hotkeys would cycle pressing 1-5 in your WoWs while letting your play normally in LoL. You could then expand upon this however you see necessary.

Perhaps someone currently running HKN can see if I've made any glaring mistakes in this.