I haven't a technical solution either, but what comes immediately into my mind is the question "Why do you have that many different batches on hand?"
Is the quantity of one batch usually smaller than a sales order quantity, so that you have to fulfill one sales order with several batches?
we are trying our best to pick FIFO, hence we have usually just one batch which has already picks while other batches are still complete in stock. And based on the batch sizes we often have just 1 batch in a delivery or 2 batches if the remaining quantity from the older batch is not sufficient to fulfill the entire order.
Hence having more than 2 batches in a delivery is then an exception can be done with manual intervention, especially as even such customer requirements are not the standard.
But what will you do, or what will the customer do, if you tell him that you can only fulfill the order by delivery from 3 batches or you would need to reduce delivery quantity to meet this requirement of 2 batches? Often the reality looks much different to the wishful thinking.