Apply a rate from other tables with conditions

[marqupcmb]

Dears I'm new with QlikView, have done some simple models that work great but know I'm struggeling with something.

I have 3 tables comming from Excel Files (Image 1)

Two are associated by field BL.BL the other one (REBATES) is making me struggel.

The table REBATES is a table where sales register special rebates for customers but can depend of differents conditions.

For example it can apply by REBATES.MatchCode or REBATES.RAAPLIC  or REBATES.HSCODE and REBATES.MatchCode and have a period of validity

All those fileds are represented on the other two tables as follow

REBATES	WEBFOCUS	finalbls
REBATES.MatchCode	MRMATCHODE
REBATES.RAAPLIC		BL.RA
REBATES.HSCODE	HSCODE

So what I need to do is on script create a value were I can assign the RebateUsd corresponding for each BL.BL not all will have then should be 0.