No-intro romset's doubts

[Carl.J (CJ)]

why in some no-intro romsets come one game whit 2 region on it?
for example in genesis/megadrive romset comes In many games

(USA, Europe)

(Japan, USA)

(USA, Korea)

(World)

is various regions on one rom
one example this wont happen in Snes romset
the normal it would be

(USA)

(Europe)

(Japan)

or whatever region have to be

and if i want to play only the europe Japan or usa version how i do it ?
Explain this Please

[Warrior]

Those are the regions that game cart was released in hence why it shows multiple countries in the filename, the rom hash is identical , if it was not identical the countries would be separated, only difference of them would be the carts label.

For more information regarding a No-Intro rom check here,

Download Links:
Links are hidden from guests. Please register to be able to view these links.

[Carl.J (CJ)]

Those are the regions that game cart was released in hence why it shows multiple countries in the filename, the rom hash is identical , if it was not identical the countries would be separated, only difference of them would be the carts label.

For more information regarding a No-Intro rom check here,

Download Links:
Links are hidden from guests. Please register to be able to view these links.

But the Snes and other romsets dont have that
and the europe version carts run in 50Hz how is supossed to run 2 regions at the same time?