Raise one rent, raise all of them to prevent false claims of discrimination?

[Troy L.]

Hi, I have  four sfr properties that I rent out for my personal income as well as a business investment.  They are all on a month to month agreement and have all been there a year or more. One of the properties is a three bedroom with no garage that the tenants pay on time but require more of my time than the others .

The properties  rent is more under market than the others as well but I raised their rent a year ago and I plan on raising it about three percent again this year according to state law.  My question is I haven't raised my two bedroom rents at all because they are close to market value in my area.  The tenants in the 3 bedroom rental aren't in a protected class but I do not want to get in any kind of legal bind.  It is not retaliatory in nature also.

Is it legal to raise rents on one property and not all of them?