A bit of a guess in the absence of more detailed context information, but my gut feeling tells me that 'afdeling beheer' might very well refer to the property management department within this real estate agency.

Sinds jaar en dag heeft Alpha Makelaardij een aparte afdeling Beheer. Wij nemen graag uw zorgen voor uw verhuurde woning en/of bedrijfspand uit handen. Huurbetalingen incasseren, een klachtenadministratie bijhouden en problemen oplossen? Laat ons het voor u regelen!
http://www.alphamakelaardij.nl/diensten/overige/

Almost every real estate agency, as well as running a sales division, incorporates a property management department into the business. The property manager is responsible for (as the name suggests) ‘managing’ a portfolio of rental properties. Usually, these properties are predominantly residential however commercial properties may form part of the portfolio.
http://www.edgepropertypeople.com.au/for_candidates/roles_in...

http://www.reinsw.com.au/imis15_prod/web/Posts/Latest_News/2...