The value of object tRPAdminCommunityExprString1 specifies
an expression that matches AS Numbers or Community ID's.
The objects tRPAdminCommunityExprString1, tRPAdminCommunityExprString2,
tRPAdminCommunityExprString3 and tRPAdminCommunityExprString4
are substrings that form one string of type TCommunityExpression.
Substrings can only be set to a non-empty string
if the previous substrings are non-empty.