Can You Suggest the best eCommerce Solution to this?

[ASG11]

Was about to post this question to WarriorForum, but then I through BBHF would be a better place to ask this question for genuine suggestions.

Okay, I am a designer, a t-shirt designer to be precise. I have been into this business for about 1 year now. I have some "very popular" designs hosted on 5 different t-shirt fulfillment websites(Skreened, Spreadshirt, etc.). The design count is about 80, and as I said earlier, they are not generic, run-of-the-mill designs. I add about 1-2 designs in a week, focusing on quality and content in the design rather than "anything goes" or "all text" designs you usually see. This has been my philosophy since I started last year. I have come to a point that I get upto 200 hits on each of these micro-sites daily. Yes DAILY.

I am able to earn good amount of money, simply through organic traffic, e.g. on Skreened, which is my highest traffic store(~400 daily hits) - 80% of traffic is organic.

I have a FB page, Twitter handle, Pinterest account to promote my designs, which are not very active. Now here is the problem. It becomes kind of difficult promoting 5 different stores on social media. E.g. X design is hosted on 5 stores, but for the sake of promoting on social media, I have to choose to promote only one link at a time. If I promote same design with 5 different links in different posts, it begins to look like the a spam page which has no other content.

So, in short, is there a solution(preferrably WP based), where I can host the design on my website, and it gives the visitor to choose the store from where he wants to buy(may be the price is also listed on my website for how much each shirt costs on each store). Once the visitor clicks/chooses that store, he is taken to relevant/checkout page on that store?

I tried fiddling with WooCommerce, but this didn't seem to be an option with it.

Thanks much, for reading through. :)