Hi:
OBi 200 series devices support up to four separate Google accounts per device, and multiple OBi devices can be authorized to the same Google account(s). In other words, you can easily have both GV numbers set up on SP1 and SP2 on both OBis.
You said that connecting the two OBis to the two-line phone didn't work. It should simply work. One possible issue is that most two-line phones have two jacks: one jack supports four-wire phone cords for two separate lines (L1 + L2), and the other jack just supports a two-wire cord for L2. Use two, two-wire/two-gold pin telephone cords; one for each OBi, and plug the cords into the two jacks on the phone. If the phone has a switch that controls the way those two jacks are used (L1 only vs L1 +L2) then make sure that the 4-pin jack is only being used for L1.
OBi #1 <---two-conductor, two-pin cord--->L1 jack on phone
OBi #2 <---two-conductor, two-pin cord--->L2 jack on phone