(court affirmed Tax Court's determination that plaintiff's exchange of properties does not qualify for deferral of gain under I.R.C. Sec. 1031; transactions were structured to avoid the related party restriction of I.R.C. Sec. 1031(f) via a series of transactions which also were designed to allow related parties to receive nonrecognition treatment while cashing out of investments using basis-shifting provisions of I.R.C. Sec. 1031; but a principal purpose of the overall transaction was tax avoidance and, thus, I.R.C. Sec. 1031(f)(4) violated).