There is nothing in the Code that prohibits a bifurcated section 6166 election.
A section 6166 bifurcation election allocates the total extended tax between two closely held business values. Each business value exceeds 35% of the adjusted gross estate. One business value might qualify for a regular 6166(a) 14-year deferral, while the other business value might qualify for a 9-year deferral under sections 6166(b)(7) or 6166(b)(8)(A)(i) or a 4-year deferral under sections 6166(b)(8)(A)(ii) or 6166(b)(10), or a separate 14-year deferral under section 6166(a).
