Co-site Cells are already synchronous, and, that´s the purpose of the MAIO, as Rami just said.
The MAIO will say to the TRX, with which frequency it should start hopping.
And as said before, the same HSN with different MAIO will make the TRX´s hopp in a same sequence but with a offset in the frequency list (they´ll begin in different frequencies to avoid co-channel or adjacent collision).