Define two different loggers one at INFO level and one at DEBUG level in you log config file as below:
#Logger option with DEBUG for package1
log4j.logger.com.package1=DEBUG,DebugFileAppender
#Logger option with INFO for package1
log4j.logger.com.package1=INFO,InfoFileAppender
log4j.appender.DebugFileAppender=org.apache.log4j.FileAppender
log4j.appender.DebugFileAppender.File=debug.log
log4j.appender.DebugFileAppender.MaxFileSize=100MB
log4j.appender.DebugFileAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.DebugFileAppender.layout.ConversionPattern= %5p [%t] (%F:%L) - %m%n
log4j.appender.InfoFileAppender=org.apache.log4j.FileAppender
log4j.appender.InfoFileAppender.File=info.log
log4j.appender.InfoFileAppender.MaxFileSize=100MB
log4j.appender.InfoFileAppender.layout=org.apache.log4j.PatternLayout
log4j.appender.InfoFileAppender.layout.ConversionPattern= %5p [%t] (%F:%L) - %m%n