How to find the cheapest destination for a meetup of friends from several countries?

From time to time a few friends of mine and I are meeting in a European place. And time and time again, finding the best airfares is a problem. Basically, we're trying to assess a possible destination and one of the important questions is how can we all get there for a reasonable price in a reasonable amount of time.

Is there any website which can do a query multiple flights at once and get a summary for the cheapest non-stop flights? Ideally, I'd like to put in multiple options for the origins and the destination, just in case there are cheaper flights for alternative airports.

Example: Let's assume we'd like to visit Vienna (VIE) and given that Bratislava (BTS) is close, that'd be a possible destination too. Let's also assume people are visiting from Basel (BSL with ZRH close), Stuttgart (STR with FKB close), London (LHR, LTN, STN, LGW, LCY), Berlin (TXL and SFX), Munich (MUC) and Cologne (CGN & DUS).

So in total we'd want to search the following return flights:

• BSL/ZRH -> VIE/BTS
• STR/FKB -> VIE/BTS
• LHR/LTN/STN/LGW/LCY -> VIE/BTS
• TXL/SXF -> VIE/BTS
• MUC -> VIE/BTS
• CGN/DUS -> VIE/BTS

Right now I find Google Flight Search to be the quickest option because it's easily possible to alter the search and also enter multiple origins and destinations separated by comma (see example).

I just wanted to ask if anybody is aware to formulate all these queries together in one flight search engine and get a summary.