You seem to be a little confused about LRECL vs record length. A file has one LRECL (logical record length) which for VB records is the maximum length of the records in that file. Each record has a record length that gives the length of that record. Records can have different lengths with a maximum length equal to the LRECL. So the records from a file with LRECL=532 can have lengths from 5-532 and the records from a file with LRECL=173 can have length from 5-173. Thus, for example, you can't tell if a record with length 80 came from the file with LRECL=532 or the file with LRECL=173.
Now if you're saying that all of the records from the file with LRECL=532 have a length of 532 and all of the records from the file with LRECL=173 have a length of 173, then you could get the 173 byte records using this DFSORT INCLUDE statement:
But that would be unusual for a VB file since having different record lengths is kind of the point of using a VB file.