Assuming that it’s the old .SUE file type from a couple decades back, you might try to copy it and give the new file a .ARC extension. Then see if any common decompress function can handle it. (Create a copy to keep the original safe.)
 
However, to compress into .SUE format might require creating your own program. You’d need to locate documentation that describes the .SUE structure. And you might be able to modify an early version of the old arc program (source is still available) so it creates a .SUE file. But I can’t think of any good reason to do it since newer compression functions work better, and no one can use .SUE files.
 
You might also try any widely used site such as craigslist to advertise your need for a program that provides the function. It’s likely that there are copies stashed around the world. Posting to any number of newsgroups related to programming might also get you in touch with hobbyists with libraries of old/obsolete programs.
 
Tom