Set whether properties that do not have a price for the specified booking condition are shown at the bottom of the property list or not shown.
*'''Sell Priority''' will display the properties in the order selected in SETTINGS-> BOOKING PAGEENGINE -> PROPERTIES-> MULTIPLE PROPERTIES-> PROPERTY SETTINGS.
*'''Unavailable at bottom" will display properties which are not available at the bottom.
*'''Hide Unavailable''' will not display properties which are not available.