Here's what I told you before..
If you want a Menu to work by broadcasting, you need a Mapped Key that has a
Do Menu Button Action in it. This Action has basically no options and defaults to "Do the Menu Button the cursor is currently over (mouseover)". All you need to do is set the Target. The Target is the window that should perform the Menu Button.
The idea is that you have broadcasting mode on, so you are able to position the cursor in the desired window all you want already. Position the cursor over the button, and then send this window a Do Menu Button Action that says to do the button the cursor is over.
This is simple enough so far, right? So you can test the concept just with the above information, by setting up one Mapped Key with a Hotkey of your choice, with a single Action in it that is super simple, in combination with Broadcasting Mode.
The "difficult" part comes where you have 45 different Viewers showing different windows, and you want to set up a single Hotkey to activate the mouseover button to whatever the Target of the Viewer you're using at the time is. This is where I added on to my suggestion to you, because to do this you would want to set up something that activates or turns on/off when you mouse over the viewer -- that is, you mouse into viewer 1 and it turns on a Hotkey that sends the Do Menu Button Action to viewer 1's Target, while if you mouse into viewer 2 it turns on a Hotkey that send to viewer 2's Target instead.
You may be able to work it out to where you have one Mapped Key that sends the Do Menu Button Aciton to an ATG, and then you set it up to join/leave the ATG as you're mousing over your different viewers. You can set up the join/leave ATG mappings using the Mapped Key Wizard's "Action Target Group Toggler" option, and then assign these Mapped Keys to each of the Viewers as the mouseover (enter/exit) mapping. This method will have a slight possibility where you could mouse into the viewer and click real fast before it has time to switch the ATG, but it should happen fast enough. I think that's about where your eyes glazed over, but this is how you would do it!