From the basics of Black Litterman I understand that each view on a stock is implemented via the pick matrix P with the expected value of the views in Q. I have read several papers where each stock with a view is incorporated with a single entry in the P and Q matrices (for simplification I am assuming here absolute views only and no relative views). Is it the case that you can only have one view for each asset? Or is it possible to have multiple views on the same assets and incorporate these through the Black-Litterman approach?
For example an asset may have multiple views generated according to several independent factor models or forecasts from several different analysts. Does the BL framework allow for this and how would this be implemented? Is it feasible to also account (from a risk perspective) for the correlations between higher level groupings such as sectors, regions or other exposures, for example?
