When selling a multi-family property off-market (not putting it on the MLS), it's common to market the property by contacting owners of similar buildings in the area and asking them if they want to increase their holdings. That same process may work for you.
You may also want to search for "syndicates" (a very specific legal term in real estate) that are operating in your area. In their most simple definition, these are typically groups that look at deals and offer them to their mailing list of investors. Anyone can start a syndicate, though most are led by real estate professionals or experienced investors, since their operation is subject to Department of Real Estate regulation.
I find that the best source for this information tends to come from mortgage brokers and hard money lenders. These professionals routinely work with individuals who are eager to make good real estate investments are are also fairly liquid to make investments now.
However, and I will caveat this greatly, most investors tend to work with other investors they know personally or with individuals who have a proven, verifiable track record. They seldom work with individuals outside of a specific group, and will typically deal only with the following as the "lead" for their investment organization--attorneys, CPAs, financial analysts, developers--and only with other similary cash liquid investors. If you are not blessed with lot of money and don't have a proven investment track record to present, it's very difficult to attract these people to come join you in your investment. More likely what happens is that they will take your idea and tend to find an even better one that they'll exercise without you.
Your best bet is to work with friends and family members to obtain the money you need to make an investment. Contact an attorney to find out how to set up a corporation where everyone buys stock and invests in buildings. These are called REIT or Real Estate Investment Trusts, and they work for a large number of investors. Also, consider having a professional run your investment by joining a fund where the lead person is an investor who understands the market and selects the properties for investment by the group.
Especially now and without experience, the investors will simply not invest in any building or home you suggest. Again, they'll likely work around you and cut you out of the deal, if its a good one.
Area Pro Realty
Oggi Kashi - 415.690.3792 direct
Broker Associate, Paragon Real Estate Group CA DRE 01844627
All data from sources deemed reliable but subject to errors and omissions, and not warranted.