You might find my new where()
expression function helpful:
In this case, your transform would look something like this:
where({value},
({path.to.District.Dropdown.custom.SelectedValue} != '<All District>' && {path.to.District.Dropdown.custom.SelectedValue} != it()['District']) ||
({path.to.Foreman.Dropdown.custom.SelectedValue} != '<All Foremen>' && {path.to.Foreman.Dropdown.custom.SelectedValue} != it()['Foreman']) ||
({path.to.Pumper.Dropdown.custom.SelectedValue} != '<All Pumpers>' && {path.to.Pumper.Dropdown.custom.SelectedValue} != it()['Pumper'])
)
I suspect this will run much faster than any script transform.