use a supplemental variable as a where clause

I want to use a supplemental variable as a where clause in variable-level-metadata, how to use P21E to generate define 2.1?

For example: a study is set up based on SDTMIG 3.3, --TSTOPO should be stored in SUPP-- instead of parent domain. We would have two rows for ISORRES in variable-level metadata, one row is SUPPIS.QNAM=ISTSTOPO and SUPPIS.QVAL=QUANTIFY, the other one is SUPPIS.QNAM=ISTSTOPO and SUPPIS.QVAL IN (SCREEN, CONFIRM). 

Could we make it via P21E? I can't find the supplemental variable here.