Linking a concatenated field

Hi,

Looking for some help in linkinga concatenated values.

I have a form which has files NAME, Mobile no, Arrival Date.
In my sheet i make a unique pair column,(Name- Mobile no.) as concatenated value.

Final display should be any new enteries having code entered for the first time. and if a unique pair is entered multiple times then only its last arrival date( modified value) shoul be visible and not the old values.
Also i want to link this table with another table by linking concatenated values. and then count the number of entries for each unique pairs

Example:

Name1-Mobile1 and Arrival Date1 (DISPLAY)
Name2-Mobile2 and Arrival Date 2 (NOT DISPLAY)
Name2-Mobile2 and Arrival Date 3 (DISPLAY - as arrival date has been modified by user with same unique code pair)

Please share your thoughts, as iam not able to link concatenated column. Thanx