add "add" operation on the derived set

[ankohuu]

Is your feature request related to a problem? Please describe.

Multiple calculated sets are all intended to be added to the derived set.

Describe the solution you'd like

use "add" operation to add some calculated set S' to the derived set, add the following to any command that calculates S': /setOperation add

Describe alternatives you've considered

No response

Additional context

No response