XML Schema: Restricting Element Value Based on Another Element's Value

Is it possible to define a minExcusive restriction based on the value of another element in the instance document, rather than on a hard coded value? For example, I have a data types defined as follows:

   <simpleType name="Milepost">
      <restriction base="decimal">
         <maxInclusive value="2000"/>
         <minInclusive value="-100"/>
         <totalDigits value="7"/>
         <fractionDigits value="3"/>
      </restriction>
   </simpleType>

   <complexType name="MilepostRange">
      <sequence>
         <element name="start" type="efms:Milepost"/>
         <element name="end" type="efms:Milepost"/>
      </sequence>
   </complexType>

In the MilepostRange type, I would like to create a restriction that requires the end milepost to be greater than the start milepost. Is that possible in an XML schema?