Disable add action on table for M2M

Whenever M:M grid is added to the form view the Add is always present

This is when no item added

This is when at least one item is added

In my case addition of item is implemented by separate rule using "create new related record with relationship" .

In my context the add action will lead wrong relationship because this out of box action is equivalent to "create relationship"

So I dont want "Add" to appear or at least it should be disabled.

What is a way to achieve this?

Best regards,

Uday Joshi