Rent Control question

[Jacob Camilliere]

So my family has owned a 6 unit (4 bed/1 bath units) apartment complex in westchester, NY for almost a century, and I think it is time to see if there is any way we can get round the ridiculous rent control. The rule in my town is any building with 5 or more units is subject to rent control. The thing is my grandparents (the landlords) have lived one of the first floor units for the past 50 years, and the other first floor unit has not been rented out in almost 22 years. We save it for when family visits, holidays, etc. There are some issues with one tenant in particular who has lived there since the late 70s probably and only pays around $800 a month because of the rent control. Shes very old and i dont think my grandparents want to subject her to moving but they would be willing to increase her rent if they could. The other units are being rented for anywhere from $1,800 to $2,500 a month. 

Would it be worth it to hire a lawyer to see if theres anything we could do since technically only 4 units are being rented and the landlord/owner lives in the other two units?

or something we have considered in the past is split each apartment into 2 bed/1 baths and increase the total amount of units from 6 to 12. I dont think my grandparents are willing to tackle a project that large but maybe in the future. 

thanks