Are both schools combining into one buidling? If so then I would definitely recommend ultimately combining into one. You may need to make one your "primary" while you spend down the other's existing funds. Being that this happens next year I have to recommend opening up communication channels between your President and their President in the near future.
This way you can start to look at their Bylaws and they yours. What events they hold and which ones you do. What fundraiser you have wnd what do they have. It will be easier starting that process this year than waiting.
If these two schools will become one but have a separate site, which I have heard of on these boards, then you can probably keep things as is. One for site A and one for site B.
The elementary school that I'm currently the secretary in the PTO will be combining with another grade school in the year 2009-2010. We still have some time, but I was interested if there was anything we legally had to do. We were thinking it would be best for both schools to have a combined PTO for at least the first year. In the spring of 2009 each school would elect their PTO and then we would have a combined PTO. As long as the PTO membership votes to change the bylaws and it is passed in agreement is there anything else that we need to do legally ? Thank you for any advice and for your time.