Slowy going through the manuals, so far looks like only the F58 allows full control, the F20 triggering only, and other flashes can't/don't control at all.
Someone somewhere must have this listed in a simple format...
In the amazon page (well, here in the US) and I believe Sony Style. It says the F20AM cannot be used for ratio groupings, just triggering as you said.
Sony HVL-F58AM Bounce-Shift Flash
Tamron SP 17-50mm F/2.8 XR Di II LD Aspherical (IF)
Tamron SP 70-200mm F/2.8 Di
Sony 50mm F/1.4 SAL-50F14
Sony 100mm Macro F/2.8 SAL-100MF28