In Compass, can we programatically set a field to be exclude-from-all?

Question

I have an Object which as a HashMap. I use a Converter to iterate over the properties of the HashMap.
In my .cpm.xml file, I define the property as follows:

    <property name="properties"  exclude-from-all="yes" converter="excludeFromAllConverter"/>

but it seems like all the fields I include in my converter are added to the "all" property.

Is it possible to exclude a field to be part of the "all" index in converter class?

I tried the following in my converter's marshall method, but it also didn't seem to work:

ClassPropertyMapping classPropertyMapping = (ClassPropertyMapping) mapping;
classPropertyMapping.setExcludeFromAll(ResourcePropertyMapping.ExcludeFromAllType.YES);

I don't want to globally turn on exclude-from-all, as I have another HashMap whose properties I want to be part of "all".