Consider the use of a numeric SAS format, which can be setup to handle ranges and explicit values. The SAS FORMAT procedure can be used to generate/maintain your values, either as instream code using a VALUE statement to build the format, or by using an external data file with the ranges / values, and then use a DATA step to read up the external file, build a SAS file suitable for use with PROC FORMAT and CNTLIN= to generate the format. Then you would use a PUT function in your WHERE statement rather than specifying a range.
Have a look at the SAS support website resources
http://support.sas.com/ for references to PROC FORMAT, and my recommended approach which is to use CNTLIN=.
Scott Barry
SBBWorks, Inc.