Tying in Wood Furnace with Geo Questions...

What is standard procedure for you guys when tying in a wood furnace duct together with a geo?

When the wood is going the blower will pretty much always be running but then how do you make sure you don't get the geo blower sending air back down the chute to the furnace? This can all be considered new construction.

I'm looking for the best option possible....

My 2 supplies and 1 air return come down on the right of the chimney flue which is where the geo will sit.