I know Mia way outranks me, but my experience and opinion is different. For years I only had the same Blue cash card you have. Last year, I applied for a PRG and a Gold Biz for 100K X 2 MR bonuses. The cards were automatically linked on my online account and the points I had with the Blue and earned on the other accounts were all pooled on the same MR rewards account at the benefits level of the Gold cards.