The following contents are copy from sap.javaeye.com.
Info record can be created not only for material but also for material group.
This is used for consumed material or non-stock material purchasing.
Just input vendor/purchasing organization and leave the material field blan, then enter, SAP will require you to key in material group.
Please refer to the SDN thread.
https://forums.sdn.sap.com/message.jspa?messageID=7364347
or download the pdf file.
http://www.easy-share.com/1907419813/Non_stock_material_info_record.PDF