First off, it is not important if You have Chapters in Africa.
You are in Amerca and need to concentrate on here rather than there.
I too started a Local and it is very trying. We did not expand as it was with The Specific idea of Affiliation with a National Organization.
If You are planing to try to expand Your Organization, it is going to take a tremendous amount of work by all Members. Try going to Colleges that are near or where You members have Friends to see if they are interested.
I take it if You are talking about Africa then You may be of African Origin. Is this a Black Group?
As boots49EPY said, You can have a Local that is not recognized by Your School, but it will be a little harder. You do have to be known to expand.
Good Luck!