Have 2 questions:
1 - Where can I find configuration for roaming beetween AP's in 1 WLAN?
For example, client with signal worst then -68dB have to roam to another AP.
2 - How can I limit/prohibit raffic beetween Wi-Fi clients?
For roaming you have the minimum basic rate and power settings to encourage roaming, plus the probe suppression you already mentioned. Ultimately the roam decision is down to the algorithm used by the client manufacturer, for reference check out these articles:
