Redirect call to internal analog extension

Hello everybody!
I have next configuration, analog PBX, PSTN Gateway Grandstream GXW410X, FreePBX server, analog phones and VOIP Phones.
I manage system in next way, from VOIP phone i be able to make a call to special extension (2000) and get into Gateway GXW410X, so after i hear beep and i dial internal number analog phones and speak with abonents.
I have the next question, when i recieve a call on my VOIP phone, i would like to redirect this call to internal analog extension, but i could only redirect to (2000). So how i can manage system and bind some extensions or something else, that they be able to call to extension 2000 and after beep, dial internal analog extension in automatic mode? For example i dial 2005 - and literally i dial to 2000 and after beep to 106 (internal extension) automatic. Hope you understand me.
Thank you.

Thank you for reply.
Great idea, as i understood from your speech, i have to choose one extension, and use follow me system and fill in Follow-Me List necessary numbers in next format [number]www[internal extension], for example - for an extension 1005 - Follow-Me List - 2000wwww114 (where is 2000 SIP Extension which allow to enter into analog PBX and 114 an analog extension)? But when i did it, system changed my number to 2000114#, and of course nothing happened.