How should I insure all my properties?

[Justin Franklin]

As I grow my portfolio, I'm thinking I should standardize my insurer. I own property in CA, MI, IN, TX, CO and PA...and I have 6 different insurers. Any guidance on a company that can provide a solid one stop shop for me? In a perfect world, I'd be able to have on agent or broker to handle insurance on all properties! 

I'm also getting concerned about liability insurance...any recommendations on umbrella policies?

Thanks!