If several keys are inserted into a search structure (or deleted from it) at the same time, it is advantageous to sort the keys and perform a group update that brings the keys into the structure as a single transaction. A typical application of group updates is full-text indexing for document databases. Then the words of an inserted or deleted document, together with occurrence information, form the group to be inserted into or deleted from the full-text index. In the present paper a new group update algorithm is presented for red-black search trees. The algorithm is designed in such a way that the concurrent use of the structure is possible.