How to make Magento apply the attributes assigned to simple products to group products they are assigned?

We are a wholesale jewelry company that sells to retail businesses. A given product code ( say product ABC) is available in 3 different colors. For example, Grouped Product ABC is linked to Simple Product ABC blue, ABC red, and ABC green. Note: We have decided to not use Magento's configurable products mainly because we need to track inventory for each ABC color option.

First, question... Is this a sound approach?

Second, we want to use layered navigation. That is, the customer, will choose "Blue" from the list of color attributes and will see all the Grouped Products that have "blue" simple product skus assigned to them. In other words, the individual products are hidden and only purchased through the group product. One way to accomplish this is to create multiple select attributes and apply them to the group products. That's not very efficient though. Since all our products share a common set of attributes, why can't magento look at the simple product that make up the group product and use those attributes in the layered navigation?

So my question is this.... For layered navigation is it possi开发者_运维问答ble to make Magento look at the attribute assigned at the sku level instead of the group product level? This would keep us from having to assign multiple select attributes for all our grouped products.