Hi Munsif,
Using the role property is possible, but you have to know the clue. You can create a new temporary table called e.g. MyRegions with at least the field region. Then create an method called XDS. In this method, create records for this user belonging to one or more teams based on the team assignment with x++ coding. this is like other My... tables. within this method you can use your logic that the teams codes are equal to regions.
Then create a query where you can join the sales table directly or first the region table with the new MyRegions table. Create a new policy based on this new query. Then you can use the role property without creating multiple roles.