If you're going to run this in a script. Why not hardcode the various block names into the lisp, then use your ssget with something like this:
(ssget "x" '((0 . "INSERT") (2 . "blkname1,blkname2,blkname3")))
The string of block names you could set as a global variable at the start of the lisp, so you can more easily add / remove any blkock names at a later stage.
Then the only thing you have to worry about is the attribute tag names, which may of course also vary.