Hi Bri's,
Not sure about a central nest. If it is indeed red spider mites that you have,which is a common house plant pest, the tell - tale signs are bronzing of leaves with fine webbing on the undersides and around the bases of plants. these tiny spider-like mites can multiply very fast in hot dry weather, although they can be affectivly killed off with house plant sprays containing malethion or deris.
If its the larger and harmless velvet mites you have, the can commonly be seen on walls and pavements then I'm told that tea tree oil smeared along windor sills can stop them entering. Good Luck. T bird+