definition of drainage areas

[jpl78]

I'm new to SWMM so this question may be too easy to answer...

I'd like to know if there is any option that SWMM can define the drainage areas for each sewer manhole (or inlet) automatically?

It is very time consuming if the sewer network is large and the definition of the drainage areas have to be done manually for each manhole (and inlet).

What is the common procedure in these cases?

I appreciate your help.

Regards,
Joao