Lookups in a portal

I wonder if anyone can help?

I have tried to use the normal lookup function based on various relationship configurations to no avail. Looks like a portal is the way forward but I am not sure if you can use a lookup within the portal

I have 2 Tables

Table 1 Fields

Sample No. 1

Sample Details No. 1

Sample No. 2

Sample Details No. 2

etc up to 10 sets

Table 2

Sample No. 1

Sample Details No. 1

Sample No. 2

Sample Details No. 2

etc up to 4 sets

In Table 2 the Sample Details field is set up as a pop up list based on a concatenated value list of all the Sample No. 1, Sample No. 2 etc records in Table 1. The list of matched returned records is then reduced by a key field which I have called Sample Log Number

What I need to be able to do is to match the sample log number in Table 1 and, say this is in Sample No. 2 field of Table 1 copy the details from Sample Details 2 into Table 2 Sample Details.

Example of Data

Table 1

Sample No. 1W10000

Sample Details No. 1 Location 4

Sample No. 2 W10001

Sample Details No. 2 Location 6

Sample No. 3 W10002

Sample Details No. 3 Location 14

Table 2

We are in the Sample No. 2 field have looked up the Sample No. from Table 1 and selected W10002. We need to lookup the details in Sample Details No. 3, which in this case is Location 14 and copy these details to Table 2 Sample Details No. 2

Any ideas?

Thanks for your help again