Here's my code for pairing Negative to positive,

=IF(A4="","",IF(A4<0,-A4&"_"&COUNTIF(A$2:A4,A4),A4&"_"&COUNTIF(A$2:A4,A4)))

=IF(COUNTIF(B:B,B4)=2,"x","")

When i filter to X all pair show