declare @A table( id int identity, N nvarchar(32));

declare @B table( id int identity(-1, -1), N nvarchar(32));

declare @AB table( idA int, idB int);

declare @tmp table( id int, N nvarchar(32));

delete @tmp;

insert @A
  output inserted.id, inserted.N into @tmp(id, N)
  values(N'Пётр'), (N'Иван')
;

merge @b as b using @tmp as x on 1=2
  when not matched then insert(n) values(n)
  output x.id, inserted.id into @AB(idA, idB) 
;

select * from @A;

select * from @B;

select * from @AB;