Mixed signal design and layout

So far I am able to do a analog schematic and layout using virtuoso + layout gxl and a pure digital flow using ncverilog and place and route using innovus.

How do i actually combine both flows?

1. On innovus can I specify an area then do a place and route then import it to virtuoso and connect it to my analog blocks?

2. How is it done in industry? Are mixed signal designs only simulated on schematic level then layout?

Please provide some resources. Thank you