2 added 2 characters in body
source | link

Yes, Nick, it's possible. You can add event receiver to list and override item added event. Using this way you can code any your logic. I need warn you about possible performance problem with uniqe permissions of each item. If you don't wory about performance problems (for example, where isn't a lot of items or users), then you can use event receivers. If you wory about performance, then you might think about creating lists or folders for each company.

MSDN: Using Event Receivers in SharePoint Foundation 2010   

Sample Event Handler to set Permissions

Yes, Nick, it's possible. You can add event receiver to list and override item added event. Using this way you can code any your logic. I need warn you about possible performance problem with uniqe permissions of each item. If you don't wory about performance problems (for example, where isn't a lot of items or users), then you can use event receivers. If you wory about performance, then you might think about creating lists or folders for each company.

MSDN: Using Event Receivers in SharePoint Foundation 2010  Sample Event Handler to set Permissions

Yes, Nick, it's possible. You can add event receiver to list and override item added event. Using this way you can code any your logic. I need warn you about possible performance problem with uniqe permissions of each item. If you don't wory about performance problems (for example, where isn't a lot of items or users), then you can use event receivers. If you wory about performance, then you might think about creating lists or folders for each company.

MSDN: Using Event Receivers in SharePoint Foundation 2010 

Sample Event Handler to set Permissions

1
source | link

Yes, Nick, it's possible. You can add event receiver to list and override item added event. Using this way you can code any your logic. I need warn you about possible performance problem with uniqe permissions of each item. If you don't wory about performance problems (for example, where isn't a lot of items or users), then you can use event receivers. If you wory about performance, then you might think about creating lists or folders for each company.

MSDN: Using Event Receivers in SharePoint Foundation 2010 Sample Event Handler to set Permissions