Thus, for example, if a partnership or S corporation is engaged in the activity of exploring for, or exploiting, oil and gas resources with respect to 10 oil and gas properties, a partner or S corporation shareholder may aggregate those properties and treat the aggregated oil and gas activities as a single activity. If that partnership or S corporation also is engaged in the activity of farming with respect to two farms, the partner or shareholder may aggregate the farms and treat the aggregated farming activities as a single separate activity. Except as provided in section 465(c)(2)(B)(ii), the partner or shareholder cannot aggregate the farming activity with the oil and gas activity.
26 C.F.R. §1.465-1T
Secs. 465(c)(2)(B) and 7805 of the Internal Revenue Code of 1954 (98 Stat. 814, 68A Stat. 917; 26 U.S.C. 465(c)(2)(B) and 7805 )