This is possible. But certainly not by me.
I have asked one of my programmers and this is the response I received.
First, this is for a Sql based SalesLogix.
In your conditions you would use the modifydate field, operator would be "Less than".
In the value......make sure you check the box....."use a literal"
then.....
DATEADD ( hour , -12, getutcdate() ) or DATEADD ( hour , -12, getdate() )
It is either the getucdate or the getdate.
If you need further assistance on this specific topic.... you might try slxdeveloper.com.
Good Luck,
Dale