There are a several different ways that publics can be combined for effective Public Relations. There are 3 questions you should ask when trying to find the most effective way to combine publics. First, you need to see which publics working together will product the best overall solution. Second, you need to figure out which publics make the most sense for long-term organizational relationships. Last, you need to find out which combination of publics will get the desired result for the least amount of additional time, money and other resources. When combing publics, the PR person needs to find the combination that solves the problem, builds long-term relationships and is most cost effective.
An example of combining publics effectively is in a political campaign, when the public relations team needs to determine the best combination of voter publics that will get that person a win in the campaign. The will need to take in consideration what combination of voter publics will give the most votes, who will be most crucial to the long term success of the candidate and what will give them the most benefit for the least amount of money.
Source: Strategic Communications Planning by Laurie Wilson and Joseph Ogden