The idea would be to crete separate strat for the running of each building and then an over-arching strat scheme or community title for the communally shared services such as you described.Apart from it being expansive and time consuming to get ba ll the legals exactly right, you would still need to get the majority of people in all three buildings to agree … and that's exactly what you'd need to do to oust the current EC (only without all the legal hassle).
What you need is a coup and the best way to do that is to present a viable alternative Executive Committee at the next AGM (or an extraordinary general meeting if you can't wait).
Even if, as you say, tha majority of residents hate the current EC, your problem is going to be convincing proxy voters to support you – too many of them just give their votes blindly to “the chairman”. However, if you can convince investors that the value of their property is being damaged by the way the strata block is being run, they will come to you in droves.
Forget reconfiguring the strata scheme – take control first, then decide what to do.