(Please read at least this before answering: This is a temporary measure! No, we do not want to set up a local repository manager and manually run a script)
<I would imagine something like this would work (this will install it on every build):
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-install-plugin</artifactId>
            <executions>
                <execution>
                    <id>inst_1</id>
                    <phase>initialize</phase>
                    <goals>
                        <goal>install-file</goal>
                    </goals>
                    <configuration>
                        <!-- config for file 1 -->
                    </configuration>
                </execution>
                <execution>
                    <id>inst_2</id>
                    <phase>initialize</phase>
                    <goals>
                        <goal>install-file</goal>
                    </goals>
                    <configuration>
                        <!-- config for file 2 -->
                    </configuration>
                </execution>
                <!-- execution file 3... -->
            </executions>
        </plugin>            
    </plugins>
</build>