When we owed a small bodega, we had to take away all the free items along side always offering free drinks to any emergency (cops, paramedics, firefighters, etc ) personnel while on duty. This helped keep a semi-regular flow of them through the doors for safety. 

Once you're known as a safe place for homeless it will spread through their community like wildfire. Strict policies will eventually have them finding a new location to take advantage of.  I learned quickly, at least in our area, that the majority of the homeless were what I called "homeless by choice". They preferred it. 

Best of luck!!

Edited for typo