Looking for suggestion to mark external links, so they can be opened on a different tab in cp

Summary:

We have a widget containing links to different stuff. Articles, channels, external sites.

What we like to achieve is to add a Boolean to our channel for usefull links, that we can mark when a site is external.

The idea is to add target="_blank" code in the view of our widget, based on the Boolean from the schema.

Content (required):

Our channel schema consists of a Title, a URL and a Boolean for an External Link.

Our widget (called Linklist) is based on the standard/searchsource/SearchResultList widget (which in terms calls the okcs/AnswerList widget). The content however consists just of the document-information of the channel for links, not the content-fields of this channel.