Combining values from two MAs in a multi-value attribute

Hello,

Is it possible to combine values from two MAs (e.g. an SQL MA and an AD MA) in the metaverse and export these back out to the AD MA for a multi-value attribute?

Basically I want to set some standard email addresses from SQL, and combine these with any that might be added in AD (in other words not overwrite anything in the proxyAddresses attribute), but updates from SQL should be flowed through too.  

Any ideas?

Thanks,

Henry