Add custom text after the string in a field type: post

Hello everyone. I am using a field of type post. The result is a nice dropdown populated with IDS and post titles.I would like to know if there is filter to add some special text after the text string which appears.
Example:

<option value=3466>Post title</option>

to
<option value=3466>Post title – this is a custom string, number whatever.</option>

Kind regards
ArchimidisM