Custom Legend in a Donut chart

how can I customise the colours for my Donut chart legend? I am trying to group the legends by colour based on value.

Each country in my data has a value and I am checking if the value is either ">100%", "90-100%", or "0-90%". Now based on this check, I would like to represent it on a donut chart with custom colours. i.e if the value is ">100%" then assign the colour green.

Now, this value is stored as a  calculated column in my data.

The problem I have is, if I select a country from the slicer to display on the donut chart, I get more countries displayed than expected.