Assign specific color to a pie-chart-piece on a dashboard when number of pie-parts vary

I want to assign specific colors to pie-parts even when the number of pie-parts vary from 1 to 5 parts. Error parts are not alwys in the pie but must always be red. Completed part is always in the pie and must always be green. There are two kinds of errors that are not always in the pie chart but as mentioned must always get the same color. How can i make this work? code example of 1 piechart in the dashboard: index = fake-index sourcetype = fake-sourcetype source = /something/application.log "*Check execution performance*" AND ";G;" | table SoortToets , UitkomstToets | stats count(SoortToets) by UitkomstToets-15mellipsisNone0visiblevisiblevisiblelinearlinear0inheritpie5010areagapsnone0.01defaultshinyall00ellipsisMiddleright