While technically any transaction made on one partition can be mined into a block in the other partition assuming that the outputs of the previous transaction (inputs to the new transaction) are available in both, in practice it is more likely that transactions from one partition will only end up in that partition and both forks will be very different in terms of which blocks they have.
Also, as another reply said, you'd have to have minors connected to both partitions.
That is why the fork with the most work wins. Not the fork with the longest chain. Otherwise you could just intentionally partition your machine. Mine a bunch of blocks offline (because difficulty will adjust down as block solve time increases) and then reconnect.
