Free Shipping over certain amount on certain products

I have set up free shipping over $100 for a certain product, lets call it (Product A).



If you add only Product A to the cart and it totals over $100 it works like a champ. Free shipping is added.



If you add any products other than Product A to the cart and they total over $100 the free shipping is not added… which is correct.



Here is the issue.



Lets say there are products in the cart totaling $120. If I add a product from Product A that is $10 it still gives free shipping.



What I need is for the free shipping to ONLY be available if there is a total of $100 or more of Product A in the cart. Even if there is $1000 of other products.



I hope this makes sense.



Thank you in advance,



Scott