You have a captive audience at the end of the ceremony.  Give your wedding officiant very specific instructions to make an announcement of what comes next.  Typically family portraits happen right after the ceremony so let him know who should be included in that announcement…Aunts, uncles, cousins…or just the immediate family (Parents grandparents and siblings).  Don’t forget the rest of the guests here…is there a cocktail hour, food truck, etc?  When will dinner be served?  Give your guests guidance…they always love to know what to expect and will relax and enjoy much more if they do!