is there a way to edit multiple envelopes at the same time?

Assuming you are building a sound “from scratch”, you would construct the envelope of the first Element or Operator, then COPY that Element or Operator to duplicate it.
The COPY function appears when you are editing an Element or Operator if you press [SHIFT] + [EDIT]

If, however, you are editing an already programmed sound, where the envelopes are programmed differently, there is no way to change multiples, simultaneously.

That said, the so-called “Quick Edit” parameters, when set to COMMON, allows you to offset all Attack, Decay, Sustain, Release settings across all Elements and Operators. This makes making quick changes, totally possible.

When you are controlling a dozen or two dozen, or more Oscillators, you can be very detailed in setting up what each is doing... that is a blessing for accuracy, but a nightmare if all you want to do is change from quick attack to slightly slower attack... no one wants to have to adjust each and every oscillator individually for such a thing. The COMMON ADSR Knobs found among the Quick Edit knob parameters simply *Offset* all the Oscillator’s Attacks so you can quickly reshape a sound no matter how many Oscillators are used to create the Performance.
Press the left front panel [TONE] button to access Attack, Decay, Sustain, Release on Rotary Encoders 5-8

From the HOME screen:
Touch “Motion Control” > “Quick Edit”
Set the PART = “Common”
Here you can see the values... you can store these Offsets to the User Bank.

Extra Credit: Offsets to ADSR for each Part, can be memorized in SCENE snapshots. Each Part can have a set of eight Elements or eight Operators, you can memorize ADSR offsets by activating the AEG MEMORY Switch.
From HOME
Touch “Scene”

Sorry, if that over explains it, but it’s not clear what you are referring to exactly. Thanks for the question.

Thanks for the detailed response. 🙂 to be clear I was talking about editing multiple elements/operators at the same time. I was working on a sound from scratch where i wanted a couple of operators to have the same envelopes but other parameters were very different.

EDIT for clarity - "On the flip side of the coin, if you're not starting from scratch ..."

There's not a way to do surgical batch jobs for envelopes on Montage (EDIT: "meaning, after-the-fact affecting just the EGs all together without touching other parameters) . Software (PC/MAC) could do this - I'm not aware of what's available to do this. Even a web-based service similar to soundmondo could do this by modifying your edit buffer. Still requires a PC for web connectivity.

Assuming you are building a sound “from scratch”, you would construct the envelope of the first Element or Operator, then COPY that Element or Operator to duplicate it. After you have the envelope setup for the first Operator Copy it to the next then make the other parameters very different.
The COPY function appears when you are editing an Element or Operator if you press [SHIFT] + [EDIT]

In general that’s a good workflow with FM-X Operators... create a basic envelope for your first Carrier...copy it to the next Operator before beginning to tune the next Operator or do any other programming. If all your Operators begin with the same basic EG, it’s often easier to vary them from that similar starting point when you need to alter one or more of them.

Tried the copy function and yeah it does look like it's the best way to go. Thanks again.

I should mention that the John Melas “Performance Editor” does allow surgical “copy and paste” on things like Envelopes, between Operators or between Elements. Just Fyi.