I have one hive only.  I'm a new beekeeper (or "haver").  My bees did not
want to build comb on my plastic frames.  The local bee supply/farm supply
store has old beeswax for sale, along with other candle making supplies.  I
melted it and spread it on the plastic with an old paint brush.  Within two
days the center frames had comb developing, and the old wax was nowhere to
be seen.  Maybe the girls just then really needed the space, or maybe the
wax did it(?)  It may be worth a try for you.