Paul,
There is an includable script at xtra/signup-xtra.php. When copied to your main ListMail folder it will run after signup or optionally during manual signup and import. You can try the following custom code. If the user subscribes to List 2 their followup and seq will be copied from List 1 and they will be set to seq 999 on list 1.
if($list=='2'){
// get info from list 1 if exists
list($cseq,$cdel)=@mysql_fetch_row(mysql_query("select cseq,cdel from $utable where email like '$email' and list = '1';"));
if($cseq){
// copy from list 1 to new subscriber
mysql_query("update $utable set cseq = '$cseq', cdel = '$cdel' where uid = '$uid';");
// set to 999 on list 1
mysql_query("update $utable set cseq = '999', cdel = '0' where email like '$email' and list = '1';");
}
}
Regards