I mean... how bad do you really want this?
The alternative would be to make a "3rd receptionist" phone that isn't actually being used but there is a physical phone and place it on a back counter or something... then put multicall appearances of that that extension on the two receptionists and a MWI key... ring the DID/trunks to the 3rd receptionist phone... Call logs on phone on back counter, vmail appears on both (all 3 really) phones, and can be answered by either receptionist. Not elegant, but reliable and it works.
Otherwise, because you have embedded VM it's a challenge... you start getting into some of the 3300's "gray area" as I like to call it, routing calls with embedded VM is a challenge because EM is basically a glorified answering machine and not very "smart"... These solutions don't always work as expected or the same in every scenario... sometimes you can figure it out, other times it's just a mystery why it works or doesn't.
You can add a phantom extension as the first member in the ring group, and the two active receptionists in #2 and #3 spots... timeout the RG to voicemail and create a mailbox that matches the Ring Group extension and it SHOULD light the message waiting light on the first extension in the ring (or any non-ACD) group, the phantom that you have MWI's for on the two receptionists (you can't have a MWI key for a RG). This works most of the time... in some cases it doesn't... Then you have to use the old ACD path method to "break the original destination" from the call and attach it to the ACD path and overflowing it to VM (NOT rerouting)... it's weird and it seems it works much less reliably in newer versions than on the older MCD versions...
