Ask HN: How do you deal with continuous requests for cooperation?

I get requests for cooperations and meetings day-in and day-out (mostly also for another business I am working on) and I don't really know how to handle these situations. That is also the reason why I have stopped networking because I simply don't want to deal with all the people that send me mails that "we should do something together".

My problem:

1. I don't want to "close the door" on a potential deal or cooperation because what might not be an opportunity now, could turn into something interesting later on.

2. I can't (and don't want to) spend time meeting people when I actually should work on my products.

What is your approach to deal with this dilemma of keeping people interested and open but at the same time staying focused on your current tasks and goals?

Any recommendations to filter out the promising ones from the not-promising ones?