Do capitalists in the Marxism world view create value? As I understand it, capital is created through the surplus value, that is the difference between the value of a worker's work (i.e. the wage that he is paid) and the new value that is created through his work. A simplified example would be this:

Worker A makes 100 ice cream cones per hour and is paid 10$ per hour
Raw material for making a single ice cream cone costs 0.2$
Worker B makes 100 scoops of vanilla ice cream per hour and is paid 20$ per hour
Raw material for making a single scoop of vanilla ice cream costs 0.5$


That would make the cost for a single cone with a scoop of vanilla ice cream exactly 1.00\$. 

Cone with ice cream is sold for 2$


That would leave a profit of 1\$ per sold cone with ice cream for the owner of the ice cream shop (assuming that the building itself does not require any regular payment).

Worker A and B are paid 0.3\$ for creating a value of 1.3\$. According to Marx they are paid 1\$ too little for their work.

Is the capitalist attributed any part in the creation of this value? I don't want to talk about the fact that he owns the means of production, but rather about this: Does the capitalist create a bigger value by aggregating the work of the two workers? This is obviously trivial for ice cream cones, but I could imagine something meaningful for example in the production of cars, where the organization itself requires work. Is this work done by the capitalist considered at all in Marxism? Or is any creation of value attributed to the individual workers who in turn are therefore exploited?
I'm not a Marx expert, but I've read The Capital some years ago and as far as I can remember Marx said that only the workers produce value. All others' wages (and the workers' wages too!) and other costs are covered by the produced values of the workers, so the others decrease the "profit", which could remain at the workers otherwise. Therefore Marx suggested the workers to make collectives without any capitalists.