Yes, depending on some limitations. If the existing 80 cables do not exceed the cable run maximum of 295', then you can extend them using a 110 Cross-connect arrangement or a BIX Cross-connect arrangement. BIX has always been CAT5E compliant. Using the 110 system, make sure your 110 4-pair connectors are CAT5e rated, since several manufacturers make CAT6 also. You don't want mixed 'categories' in the transmission path. With the appropriate wiring practices, a cable extension of this type should provide maximum compliance with the TIA/EIA standard and minimal transmission impairment.
....JIM....