External number in ring group gives incorrect CID

First of all, let me just say I’m decent with the FreePBX GUI, but I’m not very experienced with much else. If you want me to do something outside of the GUI, I’ll probably need instructions. I’m running a Trixbox installation.

I have a ring group that dials my cell phone number. I have an incoming route go directly to this ring group. If I dial this ring group from another extension, I get the CID that I want. If I dial in from the incoming route, the CID that I see is the CID from the incoming number, not the one that I specified for the outgoing route.

For example, anytime my PBX dials my cell phone, I want my CID to show 555-1234 so that I know it came from my PBX. Extension 601 dials my cell phone through an outbound route that sets this as the CID. If I dial 601 from my 201 extension, it works fine. All inbound routes are directed to 601. If I dial in from another phone, say 555-9876, my cell phone CID shows 555-9876 rather than the 555-1234 that I want it to show (so that I know it is coming from my PBX).

Any ideas?