In few words, i would like to find a way to label a job description text with just one label (and not one label for each token of job description text) while at same time to label each token of the text that is not part of the job description text.
The problem is that the job description text and the job title/date/company name text are in the same block of text and I have to use just one model.

Can you clarify what you’re trying to do? Here’s what I understand from what you wrote above:

You have a chunk of text from a resume
You want to identify the span of the text of a job description.
You want to also identify the spans of text for date, job title, and company name.

What do you mean by:

i would like to find a way to label a job description text with just one label

Do you mean that after you identify the job description span of text, you want to classify that text?