public static Map<Id,Id> ownerToGroupMap;
public static Map<Id,Id> roleToGroupMap;
public static Map<Id,Id> userToRoleMap;

public static void populateDataForQueues(Set<Id> ownerIdList){
    List<User> userList = [SELECT Id,UserRoleId FROM User WHERE Id IN : ownerIdList];
    userToRoleMap = new Map<Id,Id>();
    for(User user_i : userList){
        if(user_i.UserRoleId!=null){
            userToRoleMap.put(user_i.Id, user_i.UserRoleId);
        }
    }

    List<Group> groupList = [SELECT Id,Name,Type,RelatedId,Related.Name,(SELECT UserOrGroupId,ID,GroupId FROM GroupMembers ORDER BY Group.Name ASC) FROM Group];
    Map<Id,Set<GroupMember>> queueToGroupMember = new Map<Id,Set<GroupMember>>();
    ownerToGroupMap = new Map<Id,Id>();
    for(Group userOrgroup_i : groupList){
        if(userOrgroup_i.Type == 'Queue' || userOrGroup_i.Type == 'Regular'){
            for(GroupMember groupMember_i : userOrgroup_i.GroupMembers){
                if(!ownerToGroupMap.containsKey(groupMember_i.UserOrGroupId)){
                    ownerToGroupMap.put(groupMember_i.UserOrGroupId,groupMember_i.GroupId);
                }
            }
        }
    }

    roleToGroupMap = new Map<Id,Id>();
    for(Group group_i : groupList){
        if(group_i.RelatedId!=null){
            if(!roleToGroupMap.containsKey(group_i.RelatedId)){
                roleToGroupMap.put(group_i.RelatedId,group_i.Id);
            }
        }
    }
}