You're using the CB Auto Action for outputting a CB Gallery gallery for each group or you're just using the GJ Photos integration? Regardless the tab order for groups is entirely based off the plugin load order. Any tabs output by CB Auto Actions (Activity and Gallery) should always be first since they're loaded before GJ integrations are loaded. If they're not ensure CB Auto Actions within CB > Plugin Management is ordered before CB GroupJive. If you're using GJ Photos then it's the same situation and you just need to adjust its order within CB > Plugin Management.