You can do a TRANSFER operation, (that operation is available to every user) and yes we have a great interface for TRANSFERING hundreds of cards at a time. But what needs to be understood with blockchain is that ONLY YOU can do transactions we only provide YOU with the interface to make those transactions and sign them yourselves with whatever login system you are using.

... but still you need to be able to log into that second account you own (the one with the cards in it) aka not the one you are posting from right now.
Only the keys for that account have the ability to move cards... neither anyone at splinterlands or peakmonsters has the ability to do a transfer operation the only one in the world is the person who owns the keys to that account. (That's blockchain in a nutshell for you)

We can start with a little test... just make a comment here from that other account? If you can do that it means you will be able to do the transfer operation and move the cards.