Hello Martin,
Yes, it's possible.
Following SAP notes are relevant:
1766841 FAQ: Catalog integration in MM-PUR application
1092922 Using several catalogs in purchasing
1603637 How to use multiple purchasing Catalog in EhP5? - Material Management Purchasin
Consider that for the catalog integration in ECC the SAP component MM-PUR-GF-CAT is responsible. Refer to this component for more help in SDN Wiki or OSS messages.
Best regards,
Timea