To be clear, you appear to have two objects that each look like a text box, which is a type of frame. These frames may be on the same slide in Draw, or possibly different slides. Within each frame there is some text. What you would like is to be able to link one or more characters / words (range A) in one frame to one or more characters / words (range B) in the other frame, in a manner like a cross-reference or hyperlink?
EDIT: Refer “Graphical connector” addition below, as it has been clarified that this is what is being sought.
Cross-reference / linking
The usual method for doing this (e.g., in Writer) is to insert a bookmark or reference mark (an anchor) at the destination point and a corresponding cross-reference (citation) at the starting point. Currently (under ODF v1.2) a bookmark, reference mark, or cross-reference cannot be entered into a frame. A frame object can be set as a destination (anchor) in certain circumstances (at least in Writer), but not an element within the frame. You can insert a hyperlink into a frame, but the destination can only be an entire object, rather than an element within the object.
Bug fdo#64889 and fdo#36310 are a related enhancement request pair to allow frames to be used as a destination for cross-referencing / linking. Further details can be found in this AskLO thread. There does not appear to be any related open enhancement request for cross-referencing or linking at the text-element level for frames in Draw. Any such enhancement would likely DEPEND on the cited bugs.
After clarification, it appears that visual / snapping graphic connectors, rather than the above described linking mechanism, is what is desired. There is certainly no functionality at present that would support this behaviour. Your enhancement request (if you raise one) will need to specifically state that you want text objects (words/selection?) to be treated as linkable. Doing this between frames would likely be very difficult, although that is really for the developers to determine.
Please file an enhancement bug and provide as much information as possible. Don’t forget to mark your bug as an ‘enhancement’ and provide a link to this AskLO thread. The QA team will be happy to help you triage your feature request in the bugtracker.
Please post a link to any bugs you file in a comment below using the format “fdo#123456”.