Selling stake in a property we own already

So we don't have a lot of faith in certain investors being able to commit capital. Some give their word and back out. We are thinking we just buy properties with own funds and then sell stakes to investors. For example, we buy an apartment complex at a $15 million valuation. We own 100%. We then later sell 75% stake to various investors at a $18 million valuation. I know there are JV structures, where one company will buy a stake, but its usually for massive properties and usually only two parties are involved. What if I wanted to sell to individual investors? Anyone familiar with this and and tax/legal implications? I imagine it can get quite confusing.