Is it scriptural for one congregation to invite another congregation for evangelism?

Answer:

I'm puzzled about what exactly is the concern. "To me, the very least of all saints, this grace was given, to preach to the Gentiles the unfathomable riches of Christ, and to bring to light what is the administration of the mystery which for ages has been hidden in God who created all things; so that the manifold wisdom of God might now be made known through the church to the rulers and the authorities in the heavenly places. This was in accordance with the eternal purpose which He carried out in Christ Jesus our Lord" (Ephesians 3:8-11). Technically, it is Christians who teach God's Word. Congregations support the teaching, which can include sending out teachers to other areas. The church in Antioch sent out Barnabas and Saul (later known as Paul) to teach in other regions.

Given this, there is no reason that a congregation cannot send some of its members to another area, where a congregation is weak to help them reach the lost in their area.