I *TOLD* you that using a delimited list in a single field WILL NOT WORK.
If this line of code:
NMGroups = Replace(UploadFormRequest("txtGroup"), " ", "")
results in the variable NMGroups
having the value of "1,2,3,4"
then the *ONLY* records that will match in your query are those where the field in the database is *EXACTLY* 1,2,3,4
It WILL NOT MATCH "1,2,3". It WILL NOT MATCH "1,2,3,4,5". It WILL NOT MATCH "1".
One more time: Your lack of understanding of correct database design has led you into a corner. You can't get out of this one.