No not possible. But you do not need a sync tool for this if I understand right. Plain SQL like
Code:
create table db1.newtable as
select * from db1.oldtable
union
select * from db2.sourcetable where .. — here goes your where;
rename table db1.oldtable to db1.trashtable;
rename table db1.newtable to db1.oldtable;
… will do. You can of course create a Notifications Service -job for it.