Date column matching between tables

Hi Philip, Thanks for taking your time reading this, and also coming back to me, unfortunately I'm unabe to share any sample of this data as this by nature is quite senstive, it would a large excel file type extract with contracts table with multiple columns and I would need to validate the above columns OR match them against 3 data sources:

1.First data source would be a "Commercial Impact Forms (CIF)" where I need to validate the "Start/Signiture Date" column data from the contract table against the "Effective Date"  which is from the CIF table from this source  (these are date data types)

Again from contract table two more columns: 

Supplier has access to confidential, sensitive and critical Information data column against ->Does the supplier have access to confidential / sensitive / critical information?(CIF table) - (these columns are text date types)

From the contracts table now I need to compare the:

End / Delivery Date (For open ended contracts enter 01/01/2099) column to a column called  ->  Actual End Date in (Pipeline extract table)

And a last data column from the contract table called: Supplier Segmentation Tier

Needs to be compared to a data column called Tier (Final), which sits in a Segmantation Tier table 

Hope it makes sense, so this is what I'm trying to figure out, so far I figured out that I need to create a relationship between these tables n order to be able to the matching.

Would this be a one to many relationship I need?

I would appreciate any help at this point! Thanks again!

This is how my data model looks like at the moment:

The first one is the target table  which has those 4 columns with data which need to be validated/ matched with the columns I have mentioned in my  above comment which are from data sources 2, 3, and 4.