Importing TM with context information

I'm trying to import TM from a 3rd party tool for which I would like to keep context.

For each unit I know previous and next sentences, but I would like to know how to obtain hash.

Such hash is stored in TMX file as <prop type="x-Context">8590653279671170188, 3118944222861176316</prop>

Can you help with it?

Best regards,

Marek