As you long as your stored procedure is not part of an outer transaction, it is doable:

BEGIN TRY

MERGE ...

END TRY

BEGIN CATCH

DECLARE cur CURSOR STATIC LOCAL FOR

SELECT .. FROM @tvp

OPEN cur

WHILE 1 = 1

BEGIN

FETCH cur INTO @var1....

IF @@fetch_status <> 0

BREAK

BEGIN TRY

MERGE ....

END TRY

BEGIN CATCH

PRINT 'Errors for ' + ....

END CATCH

END

DEALLOCATE cur

END CATCH

But if your procedure is part of a greater transaction, this may not work as the error may doom the transaction and you cannot do the fallback.

And of course it is a burden to maintain two code paths..