You're proposing individual tariffs on each good from each country? Talk about micromanagement.
Was that really important enough to determine the cost of goods, or were the fundamental determinants (a) objective conditions of world supply and demand and (b) general tariff levels of each country?
But even that example destroys our idea of regional markets. What regional market should Canada be in, in that situation? Should regional markets be so fragile that a tariff reduction on a single good in another continent fundamentally changes their composition?
I'm not saying it should be necessary to set individual tariffs for each country. I'm just saying that it would easily be possible in a general equilibrium world as a tariff as well as transportation costs would simply mean another multiplicative factor in the respective supply function. In practise you should probably be able to set tariffs for particular goods. After all, protecting home industries was the main motive for tariffs. If you want to punish one country in particular this could be done by altering a multiplicative factor that is the same for all goods. Hence, if you want to undermine Canada's development as the US you set this factor to let's say 10 and your general tariff for machineries of 20% gets multiplied by 10, which makes imports from Canada prohibitively expensive. This option could be integrated in the diplomatic window and it doesn't need to be a number just like none, mild, strong or severe tariff barriers. You can get easily carried away if you fantasize about these things. I could even think about some tit-for-tat diplomacy here. In concrete terms: Germany might for example offer Austria to lower its tariff barrieres if Austria does the same at the effect of both ending up with a more efficient economy. On the other hand they made themselves more vulnerable and dependent on each other. Germany and Austria ending up on different sides of alliances in a major war would definitely have its effects then. See the interaction between the polical and the economical sphere.
one more thing: there is nothing like objective conditions of world supply especially if it comes to industrial goods. Factories are only set up if there is a sufficient demand for a particular good. If tariffs on wine would be prohibitively high, Germans would rather only drink beer. This would have definite effects on French vineyards. If more industrial power acted this way (maybe because of international sanctions) it might be rationale for France to shut down its vineyards and employ more people in different sectors (I don't think this is something the player should do. If you set things up right the economy will auto adjust at least in a capitalist society).