What is the function of interest groups in the u. what is the function of interest groups in the u. s. political process? a. to collect interest on outstanding taxes owed by the people b. to determine the interest of the people on key political issues c. to determine legislator interest on key votes in the senate and house d. to influence lawmakers to pass laws favorable to thems. political process? a. to collect interest on outstanding taxes owed by the people b. to determine the interest of the people on key political issues c. to determine legislator interest on key votes in the senate and house d. to influence lawmakers to pass laws favorable to them