Pang Tong, Pang Degong's nephew, was educated in Pang Tong and Pang Degong.

Look at Zhuge Liang again: Zhuge Liang later worshipped him as a teacher. Pang Degong's son married Zhuge Liang's sister.

So Pang Tong and Zhuge Liang should be the same teacher (Pang Degong).

One more thing, Pang Tong should be a senior.