Thank you for your post.
Yes, this can be done. The most difficult part is setting up your database tables. Since one client can have many positions, and one position can have many clients (hence, what is called a many-to-many relationship), a third table is needed to keep track of the portfolios.
In the portfolio table, there would be a ClientID linked to a particular client, a PositionID linked to a particular position (stock, fund, etc.), and probably the date purchased, purchase price, amount invested, etc.
In addition, you will have some calculations that add up the portfolio for each ClientID, and some calculations to divide the sector by the total portfolio.
If you haven't worked with FileMaker Pro previously, download the 30-day trial version from our web site and start to create the tables and try to link them. This will give you an idea whether it will work for you.
Let me know if you need clarification for any of the above steps/concepts.
Is there a way to set up live feed (from yahoo finance or google finance) to get live changes of stock prices?