@paola92 - Did the answer provided by starcher help provide a working solution to your question? If yes, please don't forget to resolve this post by clicking "Accept". If no, please leave a comment with more feedback. Thanks!
I just re-read your post. I am sorry I missed the DHCP reference. I would not write the table with IP if you use DHCP. I would write only with the computer names. Then additionally make an asset table with the DHCP ranges but without computer name information. Then at least if the data is IP you will get a category displayed like DHCP-Workstation or however you tag that ip range asset object. And if the match is by name you get the more precise asset information based on your ldap info.