How to use an OHLC4 as DataSeries for the source param of an indicator ( like EMA )

Idea here is pretty simple.

I would like to set the source series of my EMA to an OLHC4 value other than the standard close ( MarketSeries.Close to kinda MarketSeries.OHLC4 )

    _exponentialMovingAverage = Indicators.ExponentialMovingAverage(MarketSeries.Close, PeriodEma);

I can't use also a custom indicator OHLC4 because the param type IndicatorsDataSeries does fit the DataSeries type

It must have a way to do this ?

Thanks