Investing using more than one SDIRA?

[Ron Read]

I have an IRA and a Roth IRA which I plan to roll into SDIRAs in the next month or so. My wife also has a Roth IRA.

I realize I'll have to create 3 separate SDIRAs to handle these rollovers since the funds cannot be comingles, but was wondering if the resulting accounts could invest jointly to buy multifamily property which none of the individual accounts could afford on its own?  The Roths are both twice the size of the traditional, so it would be about 40%, 20%, 40% equity.

If so, how would I structure this?