combine if with applymap

[#1]

Hi guys, hope you can help me:

T1:

Load BNR,

     Seller

     Resident X;

T2:

Load KNR,

     Seller

     Resident Y;

Relation:

Load BNR,

     KNR

Resident Z;

My Problem:

In T2: has each of KNR with WildMatch (DE7011*) one Seller,

     And each DE7011* Nr, hast several BNR (Bills), but the bills of the KNR, arent connected with seller.

So how can I applyMap to the seller with BNR OF KNR ?

How can I tell qlikview, that: every BNR has one seller, if you dont know it, look it in KNR and summit