It can work if you form a formal investment club. Not saying it's the best, but here's an idea:
Every April (tax refund time) each of you puts in $3,000 in cash.
Now you have $18,000. Start looking at properties, and have the LLC owned by all of you buy it. Purchases might have to wait until year 2 or 3; who knows? After 20 years your portfolio can start buying properties on it's own.
PROBLEMS: Someone is going to need money, and they are going to want it from the partnership. I would personally make it iron-clad that a partner can be bought out by one of the other partners (or an outside party everyone agrees on), but not that it can be sold at will, and not that withdrawals can be made. Someone is going to not want to wait a decade for potential dividends to pay off. Also, this approach is probably the slowest, though maybe the most doable, way to do this.