Help with formula searching for 2nd lowest value, then return value in next column

[erin78!]

I've attached a screen shot of what I'm trying to do:

As part of a larger spreadsheet, I have 7 columns of data. I want to choose the 3 smallest values in A7:A13 and average them. I can do this no problem, and the formula has been put in A2 with the correct result
[=AVERAGE((SMALL(A7:A13,1)),(SMALL(A7:A13,2)),(SMALL(A7:A13,3))]

I then want a formula to select the three lowest in ColA, and then give me the average of the corresponding values in ColB. Then I need to do the same for the rest of the columns.

For example, A9, A11 & A13 have the smallest values, so I want the average of B9, B11, & B13 (but with a formula so I don't have to chose the smallest values)

Thanks for your help!!!

[Palmetto]

=average(vlookup(small(a7:a13,1),a7:b13,2,false),vlookup(small(a7:a13,2),a7:b13,2,false),vlookup(small(a7:a13,3),a7:b13,2,false))