have (one's) hand in (something)
To be involved or influential in the planning, creation, or execution of something. It's pretty clear from the film's style that the producer had his hand in how it was directed. I'd like to have my hand in planning the party, if that's all right.
have one's hand in something
Fig. to exercise control over something; to play an identifiable role in doing something. (See also have a hand in something.) She always has to have her hand in everything. I want to have my hand in the arrangement.