Transactions that cannot be part of block Is it possible to have a "unlucky" transaction that can never be part of block? Meaning grouping it with other transactions never results in a valid block?

[Edit]
By not being in valid block, I meant no valid nonce is found with given target difficulty. It seems mathematically, this is possible and what happens to transaction (if there is no expirey) in this case?
No, if the transaction is valid then it can always be included in a block if a valid nonce/extra nonce is found.