Tie payment to certain shipping?

I have two shipping methods.

a) send the products to the costumers (mail package)
b) Pick up the products in the store.

Can you tie my payment option "Pay in store when you pick up the package." to B? Now you can select to pay in store even though you might live in another country.

If you look in the modules ... there is a setting for $this->enabled

When that value is true, the module can run ...

When it is false the module cannot run ...

To work around the $this->enabled = true for being installed, you can use a function to test some condition to control it beyond the fact that it was installed ...

Using a function that tests the shipping method, you can determin when to allow which payment module to run ...