hi Gabriel
i don`t konw whether there are a function can get the all product divisions realated this user.
but you can using @Hai Wang mentioned statement to check. you need create a authority object(SU21) with those four field, Dom. Sales Org, Direct Sales, Product Division.
then add this object to role(PFCG), in the profile, you can add some value which is this kind of role can validated. And assign this role to user. in your program, using above statement to check.
Let`s say, you add value 1,2,3 when maintaince the role.
when using authority-check object 'XXX'
id 'field1' field '4'.
the sy-subrc will NE 0. beacuse '4' is not maintaince in your role.
some technical knowledge refer this link:http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/a92195a9-0b01-0010-909c-f330ea4a585c?QuickLink=index&overridelayout=true&5003637386464
regards,
Archer