I see sponge separation as a critical problem if they are "stuck together" and "fragile/crumbly". Perhaps one could use a gentle air jet, but recognizing the boundary is the key.
Various industries use circular systems, e.g. bottling industry to fill and cap bottles, and the pharmaceutical and nuclear fuel industries use rotary presses to press tablets and pellets respectively.
Cassets could be used to contain the sponges, but still reliable separation and insertion remain key. Perhaps a head with a gentle vacuum can be used to retrieve the sponge (in conjunction with gentle air jet blowing on the interface between sponges for separation) and hold it in place while inserting it, and the gently 'blow' the sponge into the container.
God, I can't think of anything more tedious than separating sponges and placing them in small containers just so!
Well, may be I could, but why torture myself?