I was wondering if there was a way that products from one supplier would use one shipping method and products from another supplier would use a different shipping method.
 
I have one supplier that uses UPS and another who uses Fedex so it would be nice to not have the other method show up depending on supplier or at the least have the prices more expensive for the other shipping method (supplier using fedex would cost $13 to ship but to use ups with that product would cost $25 or something).
 
Any advice?

I haven't run into that need yet. I just asked Viart about determining shipping rates based on the origination point for different suppliers.
 
These two issues might have a common resolution. I'll let you know what Support comes back with on my query.