Is this possible?

[Scarlos]

1. I'm trying to play 4 chars, but in a full screen stacked window layout. Instead of switching chars I would like to hotkey, for example, 'z' to be able to hold 'z' and release control of all 4 chars, controlling only main char until I release the 'z' key.

2. Assuming the above is possible, could I then use 'x' 'c' 'v' keys to control character 2, 3, 4 while still viewing my main screen?

[lax]

Yes. You can get this one of two ways, either a) download ISBoxer 41 Beta and run the updated Quick Setup Wizard, which now includes the capability to set "Hold to Control" hotkeys for up to 6 slots as part of the wizard for Action RPGs like POE and D3. You will probably prefer the ISBoxer 41 mappings since they'll work better than the next option...

Or b) the rest of this post...

The Mapped Key Wizard can help you set that up, just go into the Wizards menu and select Mapped Key Wizard. Pick a Key Map for it to put your Hotkeys in (put them in either Combat or Non-combat), and then tell it to configure a "Broadcasting Toggler".

Broadcasting Toggler has the following options...
1. Name your Toggle: just pick a name for the button you're doing, e.g. "Hold to Control Slot 3"
2. Hotkey to activate this Toggle: This would be Z, X, C, or V in your description
3. Toggle when the Hotkey is _____: Set this to "pressed OR released", which means that it will toggle once when it is pressed, and toggle again when it is released.
4. Broadcast FROM any of these windows: If you're playing on one PC it's fine to leave this as-is, "Window:All w/ Current", but it can just as well be "Window:Current" since you'll only be broadcasting from the window you're holding the key in
5. Broadcast TO these windows: This is where you pick which window to send to, so if you're doing Slot 3 you can pick "Character Slot:3"
6. Block buttons from current window (control ONLY the Target): You want to check this box so you can control just the other window, and not also the current window at the same time
7. Popup Text for ON/OFF: This is completely optional, you can leave these blank unless you want a visual indicator that you're doing something

Note that this toggle really will turn broadcasting OFF, not back to what it was right before you held the Hotkey. You can manually change the Mapped Key to set it back to the normal state. If you want to go that far, it's probably worth your time to just download ISBoxer 41 Beta.