Les comento la solución que encontré:
el paquete enterprise de mysql cuenta con los siguientes paquetes:
MySQL-client-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm MySQL-server-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm
MySQL-devel-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm MySQL-shared-compat-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm
MySQL-embedded-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm MySQL-shared-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm
MySQL-enterprise-gpl-debuginfo-5.1.34-0.rhel5.x86_64.rpm MySQL-test-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm
El paquete MySQL-shared-compat-enterprise-gpl-5.1.34-0.rhel5.x86_64.rpm contiene los archivos para solucionar el problema de las dependencias y poder instalar directamente con yum el paquete php-mysql que era el detalle que me comentaban.
Resolving Dependencies
--> Running transaction check
---> Package php-mysql.x86_64 0:5.1.6-27.el5 set to be updated
--> Processing Dependency: php-common = 5.1.6-27.el5 for package: php-mysql
--> Processing Dependency: php-pdo for package: php-mysql
--> Running transaction check
--> Processing Dependency: php-common = 5.1.6-24.el5_4.5 for package: php
--> Processing Dependency: php-common = 5.1.6-24.el5_4.5 for package: php-cli
--> Processing Dependency: php-common = 5.1.6-24.el5_4.5 for package: php-ldap
---> Package php-common.x86_64 0:5.1.6-27.el5 set to be updated
---> Package php-pdo.x86_64 0:5.1.6-27.el5 set to be updated
--> Running transaction check
---> Package php.x86_64 0:5.1.6-27.el5 set to be updated
---> Package php-cli.x86_64 0:5.1.6-27.el5 set to be updated
---> Package php-ldap.x86_64 0:5.1.6-27.el5 set to be updated
--> Finished Dependency Resolution
Dependencies Resolved
Installed:
php-mysql.x86_64 0:5.1.6-27.el5
Dependency Installed:
php-pdo.x86_64 0:5.1.6-27.el5
Dependency Updated:
php.x86_64 0:5.1.6-27.el5 php-cli.x86_64 0:5.1.6-27.el5 php-common.x86_64 0:5.1.6-27.el5 php-ldap.x86_64 0:5.1.6-27.el5
Complete!
Muchas Gracias a todos por su apoyo, espero esto pueda servir a alguien mas en un futuro.