How to set custom group header text in GXT grid

I have got a grid with grouping possibility. The grouping column is defined as follows:

Code:

descriptionColumn = new ColumnConfig<>(elementProps.description());

I wanted to set a custom text in the grouping header but somehow only the content of the grouping column is changed when I override the render method.

Code:

descriptionColumn.setCell(new AbstractCell<String>() {
 
                                    @Override
                                    public void render(Context context, String value, SafeHtmlBuilder sb) {
                                                MyDto dto = store.get(context.getIndex());
                                               
                                                if (dto != null) {
                                                           String summary = StringUtils.provideSummary(dto);
                                                           sb.appendHtmlConstant(summary);
                                                }
                                    }
                        });

Any ideas how I can set the same text in the grouping header as in the grouping column?

How to set custom group header text in GXT grid