Build a “feature card board with highest portfolioitem as the swimlanes” - how to deal with rowConfig?

Question

I am trying to build a Feature rallycardboard group by the HighestPortfoilioItem and I am unable to create the desired swimlane. What should be the rowConfig for later added fields?

_load: function (store, records) {
    var me = this;
    _.each(records, function (record) {
       //trying to add the product to create the swimlane
        record.set('HigestPorfolioItem', me.FeaturePorfolioValueMap[record.data.ObjectID]);
    });
    this._addBoard();
},
_addBoard: function () {
    var me = this;
    me.add({
        xtype: 'rallycardboard',
        types: ['PortfolioItem/Feature', 'PortfolioItem/product'],
        attribute: 'ScheduleState',
        context: this.getContext(),
        enableRanking: false,
        rowConfig: {
            field:'HigestPorfolioItem'
        }
    });
}

Thanks!