Custom Aggregation in Material React Table

Question

I am trying to write a custom aggregation. This Custom aggregation is applicalble only for few rows and for others its default "sum" aggregation. Please help me how to write the custom aggregation and the props to that. Also, only for few rows Grouping should be enabled. I tried to have enable Grouping property in the column but didn't work.

Here is my custom aggregation Function:

    const myCustomAggregation = (columnId, cell, row, leafRows, childRows) => {
    console.log(columnId, cell, row, leafRows, childRows)
  };