RFP Question - Multiple VARs for One Manufacturer?

Hi all,

When you generate an RFP (Request for Proposal) and send it to your vendors, do you have multiple VARs (Value Added Resellers) submit proposals for a single manufacturer?

So, if you have Tech Partners Inc. as a VAR and they go to Ruckus to propose a wireless solution, can Teknologists Corp and Wi RLUS Solutions also propose a Ruckus solution?

In the past we've run into some problems with manufacturers only providing quotes to one VAR and needing to specify which VAR we want them to work with for us, but we're trying to determine the best partner here so we'd like overlap to be possible. I'm not sure what's normal here and am trying to avoid a mess where a vendor we really like reaches out later than a vendor we don't know yet and is rejected by the manufacturer because they're already providing pricing to someone else for us.

If it's one VAR per one manufacturer, how do you organize who proposes what?

(acronyms spelt out for anyone new to these terms to learn a little!)