Is it okay to hire one company for your entire retail chain security? 

I manage a well-known store in the UK, which has severalretail branches across the country. The guards for each store belong to severaldifferent companies, which is becoming quite hectic for me to manage. I wasthinking of redoing the entire security protocol of the retail chain and hiresomeone like MB4 Security (hear the name through a friend) who can take overthe security protocols across the offices. I am confused, though, whether I should take this measure,or is it better to have different vendors on board when it comes to thesecurity of a retail store?