6 Single Fam Houses. Sell one at a time? All at once? How?

[Jeff S.]

Lets say you had 6 single family homes in Ferndale MI, valued between 90k-160k each. All currently leased with good tenants, rents ranging from 1k-1,350/month. Lets say hypothetically you wanted to sell them. Without asking for specific agents, what would your approach be? Sell one at a time? All at once to an investment group? Are there people or companies out there that buy blocks of houses? How do those type of companies start their valuations? All based on rent roll, home value etc? Based on your approach, is it a residential broker you are looking for? Commercial?  Is that even a deal a novice like myself can pull off?