react-bootstrap-typeahead Custom items

I would like to customise my select element which uses

<Typeahead
            id="basic-example"
            placeholder="Choose your specialty..."
            labelKey="title"
            options={specialties}
            selected={selected}
            onChange={handleSpecialtyChange}
            size="large"
            inputProps={{
              className:
                "customRadiusSelect custom-select custom-select-lg mb-3",
                }}
            emptyLabel="No specialty found"
          ></Typeahead>

I want to customise styling of some “specialties” items and gray out them (if they are “demo” or not) etc …
How could I do that please ?
Thanks in advance.