Hi John,
Jason is absolutely correct. The easiest (and cleanest) approach to do this would be to have four DVEs per MLE, or have a 4MLE switcher, so that you can create templates using two MLEs.
Can you do a triple box by utilizing the DVEs in MLE 3, and add to the two boxes you already have upstream in either MLE 1 or 2? Absolutely, you will need to be sure to release the DVE effect in MLE 3 by selecting another transition type, either "DISS" or "WIPE," so that you don't get the warning on the touchscreen, and also having to confirm the release of your DVE resources.
Feel free to give it a try, but I would highly suggest that this be rehearsed over and over until everyone is comfortable before taking it on air:
1) You will need to make a memory for the 2-box in MLE 1, then copy it to MLE 2. Save them both in the same memory number.
2) With the 2-box memory recalled in either MLE 1 or 2, punch it up in preview. You will need this to line up the third box.
3) In MLE 3, recall memory "00" first, then save a memory that includes the third box and place it in the position that you want. Use a DSK in MLE 3 that is not being used for your lower thirds and such (I'm going to use Key 4 for this exercise). Before you save this memory, make sure all the keyers are turned off, and the third box is standing by in preview (select the appropriate buttons for in the Transition area, BKGD+Key4).
4) Go to the Global Memory keypad and select MLE 3 on the Store column, then press "ATTRIB" to go to the memory setup menu. Select MLE 3, and turn off the Preset Bus, so that when you save the memory, the Preset bus is not included in the recall.
5) Save the memory in MLE 3 only. I would suggest that you save it in the same memory number as your 2-box effects in MLE 1 and 2, just to keep things tidy.
6) Next, create a regular custom control by recording the steps of you recalling the memory in MLE 3.
In template Editor, make a template for this effect, and be sure to include the custom control you made to recall MLE 3 in the template. This cannot be "auto run" as you will need to trigger it yourself when the template is prepared (in green). This should set up the triple box effect that you want. Once you take it to air, your next template should prep, but will have the third box keyed over. You should be able to get rid of this by "un-latching" key 4, by double-pressing DSK 4 on the Rundown Control Keyer area, or press "R" on the keyboard (assuming you kept all the default hotkeys on the keyboard from the training).
****Now, the difficult part is going to be able to assign your source for the third box, as you will not be able to do so in the template (you can't control MLE 3 through the template). You can make a group of customs that route various sources into that third box, one custom per source. :) Since you have six custom control slots per template, subtracting the custom that recalls the memory in MLE 3, you still have five slots that you can use when you code this template into a story, OR, take a tab out of the Quick Recall Custom Controls, and populate that tab with nothing but all the custom controls for all the possible sources that your third box would need).
Try it out and let me know if this helps. Good luck!
Ian
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