You should pick an area (or areas) and choose one agent. If you are talking about one agent for Campbell, one for Santa Clara, one for Sunnyvale, that's what you should do. If you are talking one agent for Fremont, one for Orinda, and one for Salinas, then you need to figure out where you really want to live and not waste the time of the two other agents in the other areas.
If it was me and one or two other agents and we all knew about each other; I wouldn't expect any one of us to give you top priority for service, showing, etc. You'll be put on the bottom of the pile and miss some good deals while the agents give their best effort to the their buyers who have committed to just using them and have pledged their loyalty.
I'd probably have you sign a buyer-broker agreement if I thought you were running around with other agents. I normally don't use them in my practice but here is an example where it would protect the time, energy, and effort I put in to find, show, and sell you the right home.
Agents are generally smart and good at reading people. If I had an idea a buyer was playing this game with me, I'd have them move on to someone else. They'll find a house, someday, but things will likely not work out as well. They'll get an inferior agent doing an inferior job for them. Which is what they were asking for in the first place.
Mark Burns, Realtor
Coldwell Banker Elite - Top 2% Worldwide
President - PRDS, Contracts and Forms for Silicon Valley Residential Real Estate 2008, 2009
Chair - Region 9, California Assocation of Realtors 2009
President - Silicon Valley Association of Realtors, 2007
DRE #00896552 licensed since 1985