Seo Strategy For Ecommerce Stores

We are operating two CS-cart stores - both selling the exact same products but with different currencies and target countries. One is for our local customers with country specific domain (.in) and the other one is for international customers with a .com domain for worldwide customers and not specific to any country. Everything related to SEO that we do now is being done at double the cost and effort. We will be getting more links pointing towards the .com site.

Would it be a good idea to merge the local country site (.in) into the .com site through a sub directory like or a sub-domain like so that the SEO links benefit both the stores?