Although not ideal, one way you can do this is to use the Pop Front node and wire the Item port to hObj1 and the rest of the list to hObj2 (screenshot below)
How the Solid Boolean node works is that the first port is the "blank" and the second port is the "tool." The node will cross reference these lists, as you've noticed, to create as many combinations as possible. If only one item is fed into the first port, then the objects will all be added to/subtracted from/intersected with that first "blank" item.