With larger setups, it can be quite easy to fill 30 beds in a hospital. Expand the area and the number of hospitals and you'll find 60 or 90 or even more can be easy to fill. Then you've got to go through the trouble of adding different "wings" to satisfy the demand which costs even more money.
My suggestion is a Major Trauma Centre. It works exactly the same as a regular hospital but can have the ability to expand to 50 beds, not 30. The price - I would go for 350,000. You'd be able to expand a current hospital for the 150,000 credit difference and something along the lines a 24 hour wait (like stations). Naturally you'd also be able to buy it outright if you wish.
The benefits? 50 beds. No need to keep spending unnecessarily on hospital departments as you would if you built new wings.
I must stipulate that the traumatology department would be available in both hospitals and MTCs as is the norm at hospitals around the country.