Simple! Instead of the 8088/8087 bulkhead connector, get a supermicro 8088/8087 bulkhead and cable; then run that to the intel expander. The intel also needs a 4 pin molex for power. Then use 8087->sata forward cables to each drive, or 8087-8087 if using a backplane.
https://store.supermicro.com/85cm-minisas-cbl-0352l.html
(SM has other lengths, and has single port as well). These are on ebay.
The intel expander does dual link to HBA via a waterfall, so if you can't pull more than 2.4gb/s out of the drives there is no reason to use two cables to the HBA, but if you want to be able to daisy chain to another box get the dual connector version. I'm not sure which/if any OS may have issues if you dual link the expander like that, too....
The other, budget approach, which is slower and may not work with >2tb drives, is one of the HP expanders which has an external port. The negative of that expander is that it needs power via PCI express connector, so you need to use a mining slot to power it. It also only runs sata drives at 3gb/s, the intel runs sata drives at 6gb and works with (can verify) 4 tb drives minimum