Do you try to network all the house churches together?
Neil Cole (Church 3.0, page 96) shows three different house church network types:
A Chain Network
You stay connected only with the churches you plant and the church that planted yours.
A Hub Network:
All the churches stay connected with one central church.
An All-Channel Network:
Every church stays connected with each other.
Ideally, there is a hybrid of each of these models where some churches try to stay connected with each other as the Spirit leads.
Is there a central office or administration for the house churches?
We don't see the need or biblical equivalent of a central office.