Webhosting and inhouse exchange

I have configured inhouse exchange server 2003 which is sending and receiving e-mails.We have webhosting company also which hosts our e-mails so we did a replication and created same accounts in our exchange server also.Now the issue is half of the e-mails are coming through exchange server and half of the e-mails are coming through webhosting account which we have created as POP3 in outlook 2003 and exchange as exchange account.We have setup mx record for our exchange server as priority 1 and web hosting as 5 because if our exchange server fails still we get e-mails through web hosting client.We want to configure our exchange in htis way that we can get all e-mails through our exchange server.If i am not clear please let me know.