>
>The ID in the resulting table should be a new distincst ID, if possible.
>Regards,
>Koen

IOW Ids are not used.

Select t1.field1, t2.field2, t3.field3, nvl(t1.group, Nvl(t2.group, t3.group)) as group, sys(2015) as newId ;
from (Select field1, group ;
from Table1 ;
where !Empty(field1)) t1 ;  
full join (Select field2, group ;
from Table1 ;
where !Empty(field2)) t2 on t1.group = t2.group ;
full join (Select field3, group ;
from Table1 ;
where !Empty(field3)) t3 on Nvl(t1.group, t2.group) = t3.group