Enabling to filter for a certain Misc Info record

When I try to use alarms & notifications with the Misc Info field I cannot select, which record I want to monitor. For example: When I set the condition to  

Misc Info Description contains "A"

AND

Misc Info String contains "B"

It will create a lot of false alarms, when it finds a "B" in any of the other Misc Info String records. I would like to be able to limit this to the record described by the Misc Info Description.

Would it be possible to implement this?