Yes, that is possible, but with one exception being both dynamic end needs to establish the tunnel to the 5520 first, as they can't talk directly to each other, and it will be a hub and spoke scenario where all traffic passes through the HUB between the dynamic peers.
Here is the configuration which is required:
on ASA 5520:
same-security-traffic permit intra-interface
on ASA5510 - dynamic peer 1:
access-list permit ip
NAT exemption will need to be configured as well between peer1-lan-subnet to peer2-lan-subnet
on ASA5510 - dynamic peer 2:
access-list
NAT exemption will need to be configured as well between peer2-lan-subnet to peer1-lan-subnet
Then clear the tunnel on all ends so the new crypto ACL can be negotiated.