Belorussian and Ancient East Slavic Tribal coalitions

As part of my own efforts to clarify whether references in oral lore I have heard that say:

'...part of our group moved to [modern] Serbia, another part went towards [modern] Macedonia and the others went to [the now] Croatian coast.'

...are micro tribal references or macro references, referring to Belorussian tribal settlements or one surname, this group seeks to:

1. Collect those oral lore references to Belorussian and area tribal movements in the Balkans,
2. make them available for people to analyze.

Scholarly and other references are of great interest and very welcome, though the concentration of the group is oral lore references.

Please be as clear as possible and when required state a definition and type of reference or link.