Alcohol industry customer/supplier concentration issues?

Looking to talk to folks with experience investing, marketing or doing M&A in the alcohol industry.

I'm working on a deal for a company that provides a service to the beer, wine and spirits industry. They have significant customer concentration since payments come from distributors. However, suppliers benefit from the service and may also be involved in buying decisions. Since I know these sort of issues are common given the 3 tier system, I'm trying to understand how others have approached and diligenced those concentration issues.