Create relationship between a column values and many other columns that have those values as names

Hi, 

I have the data from a survey which contains the items as columns like so (sorry this forum deleted my html tables :( ):

id, it1, it2, it3

online1, 4, 2, 5

online2, 1, 3, 4

Then I have a relationships table that looks like this:

it, Dimension

t1, Openness to experience

t2, Openness to experience

t3, Extraversion

Now, what I'd like to do is to somehow relate table 1 with table 2, so that when I visualize the survey results, I could easily filter by dimension.

Thanks in advance!

Javier