When it comes to multiplying simple/organic churches, your pattern of multiplication will determine whether you multiply quickly or slowly.
Many people assume that the way to multiply a simple/organic church is to add new people to the church that meets in your home until it has outgrown your living room. Those who become believers, or Christians who want to join you, are assimilated into your existing fellowship. At the point at which the group becomes too large, you split it into two.
This is the slow way to multiply.
If you prefer to multiply more quickly, then start new groups around new followers of Jesus or new people who want to join you. Some of these will become churches.
Someone becomes a disciple? Ask them to bring together a few of their friends to explore spirituality. Help them to share their story with others. Teach them how to share the good news. Work with them and their oikos. You will soon find yourself with a group of new believers. An existing Christian finds your church? Let them know you'd like to help them work with their friends and family in their neighborhood, not yours. This is the quick way to multiply.
The faster multiplication pattern is likely to be more messy and more time consuming. It will involve people in more than just attending weekly gatherings. But it is far more effective in terms of Kingdom growth.
If you want to see your existing group excited about this and on board with what you are doing, it is important to cast vision, otherwise people will resent the disruption of a family/place where they are comfortable. The Lord did this for our group by giving us a clear picture of an orchard of apple trees. Now, whenever a new group starts, we are all excited to see the fulfillment of what the Lord has already shown us.