XML : Set Facet Range In Solrconfig.xml

In solrconfig.xml it defines a facet range as:

  <str name="facet.range">price</str>  <int name="f.price.facet.range.start">0</int>  <int name="f.price.facet.range.end">600</int>  <int name="f.price.facet.range.gap">50</int>    

Assuming I do not know what the range is across all price values,
is there a way to define start and end as the min and max values among all price?
Is it possible to replace the integers with key words like MIN/MAX?
Thanks!