One cognos filter and multiple behaviour

If I select query1 for 2016 automatically I can get query2  data minus1 year and querey3 data minus2 years
Automatically my below three query will filter..
[Contract_YYMM]=?yrm?
querey -2
[Contract_YYMM]=
cast(substring(Cast(?yrm? as char(6)),1,4)-1 as char(4))
+
cast(substring(Cast(?yrm? as char(6)),5,6) as char(2))

querey -3
[Contract_YYMM]=
cast(substring(Cast(?yrm? as char(6)),1,4)-2 as char(4))
+
cast(substring(Cast(?yrm? as char(6)),5,6) as char(2))