How to set a control input_index to control two joints using mavlink_interface?

Hi Guys,

I have a model that has two aileron on each side (top and bottom) so four in total.

I wanted to map the control to the joints accordingly. i.e. right_top wing/aeleron and right botton wing/aeleron would get the control from the same input index.

I set it up to the image attached

However, with this set up, only the bottom ones gets the control…

It seems like you can only map one “<input_index>” to a “<joint_name>”

Is there a work around on this? So that one input index controls two joints?

Thank You in advance