Personally, I'd stall a bit and see which of the two products starts to the win the politics war. In these kinds of mergers, it's typical for areas like sales or support to merge together before the software developers. That's when it usually becomes more clear which product is going to win out.
If it's clear, for example, that your product is going to win out, then working on "import from other product" is higher priority than "export to other product".