Clarification on Dual R3 for Controlling Two Lamps Simultaneously

Dear all,

I am currently using a Sonoff Mini R4 to control two lamps simultaneously via a single physical button. Both lamps are connected to the same output of the device, so they always turn on and off together.

However, I would like to upgrade the setup to allow the following behavior when pressing the physical button:

a. If both lamps are off, they should turn on simultaneously.
b. If both lamps are on, they should turn off simultaneously.
c. If one lamp is on and the other is off (via a Sonoff SwitchMan R5 or Alexa), pressing the button should turn both lamps on (or off—it doesn’t matter; the important thing is that they return to sync).

To achieve this, I am considering using a Sonoff Dual R3. My plan is:

  1. Connect the first lamp to L1 out using the current power line.
  2. Pull a new power line (L2 out) from the Dual R3 to the second lamp.
  3. Use a single physical button to control both lamps in a synchronized way as described above.

I would like to achieve this functionality using only the original firmware of the Sonoff Dual R3, without relying on additional software settings or automations in the eWeLink app.

Before proceeding, I have a few questions:

  1. Is the Sonoff Dual R3 suitable for this use case?
  2. With the original firmware, will the behavior described above (synchronization of the two channels based on their current states) be achievable using a single physical button?
  3. If this configuration is not possible with the Dual R3, could you recommend an alternative Sonoff product or setup to achieve the desired functionality?

Thank you for your assistance