Is it possible in Lyx to group itemize text with this symbol } ? In order to understand what i want to do , i attach a screenshot :

Is it possible in Lyx to group itemize text with this symbol } ? In order to understand what i want to do , i attach a screenshot :

Not in LyX directly but using the LaTeX functionality available from within LyX:
Go to Document | Settings | Latex Preamble
and add
\usepackage{multirow,bigdelim}
Then, go to Insert | TeX Code and in the box that comes up, enter
\begin{tabular}{ll}
Text 1 & \rdelim\}{3}{1mm}[\hspace{2mm} My texts] \\
Text 2 \\
Text 3 \\
\end{tabular}
where the 3 in \rdelim\}{3} has to correspond to the number of text items you want to enter, and the 2 in \hspace{2mm} determines the distance of the text from the brace to its right.

Does that help?