Form Auto Filling

[Viswanathan S]

Hi all,
I have a table with Columns A, B and C and also many other
Fields.

I have another Table T2 A1, B1, and C1 where values in T2,
A1 can have only those values of A and similarly for B and
C.
Now I have a data entry form. I want to enter the unique
A1 (that is available in table T1, A) and want the values
B1 and C1 back fed automatically, from T1 B and C
respectively.

How can I do that?
Thank you.
Viswanathan S