Founders & key executives

A Foundation of Values – Raised in the close-knit Temple Society, Dieter grew up with a deep sense of responsibility, learning that true leadership is about stewardship—nurturing relationships, empowering others, and ensuring long-term impact. These values became the foundation of his career.

Turning Challenges into Opportunities – At just 25, Dieter faced a defining moment when his father passed away unexpectedly. Stepping up to lead the family architecture practice, he embraced the challenge with resilience and vision. He later joined Smith and Tracey Architects, helping design spaces that enrich lives, before becoming Property Director at Regis, where he played a key role in expanding aged care services to 4,200 beds.

Building for the Future – In 2010, Dieter co-founded The Castalia Group with a vision of creating something bigger than himself—a company that integrates investment, management expertise, and strategic support to help businesses and communities thrive. Staying true to mittelstand values of authenticity, long-term vision, and social impact, he continues to champion sustainable growth and meaningful collaboration.

A Commitment to Legacy – Now a non-executive director across multiple sectors, Dieter remains dedicated to intergenerational stewardship—mentoring leaders, fostering innovation, and ensuring that businesses and communities flourish for generations to come. His story is a testament to the belief that true success is measured not just by what we build, but by the impact we leave behind.

As Director of Tingari Group, Arton Group, and Castalia Group, Lindsay has developed and executed business strategies that have significantly improved financial performance, expanded operations, and enhanced service quality. He has led initiatives covering thousands of aged care and retirement living beds, successfully securing 900+ new licences, and driving business expansion.

Previously, during his tenure at Regis Group, Lindsay played a key role in the integration of multiple aged care businesses, developed high-impact sales programs that drove significant revenue growth, and led the development of over 1,600 new beds across greenfield and brownfield projects. His expertise in stakeholder management has seen him build strong relationships with boards, government departments, and industry leaders, ensuring a seamless blend of compliance, innovation, and quality service delivery.

With a passion for leadership, strategic planning, and risk management, Lindsay continues to make a lasting impact in the aged care sector, helping businesses navigate challenges and achieve long-term success.

Andrew approaches business with an adventurous mindset, embracing calculated risks, pushing boundaries, and exploring new opportunities. He believes in tackling challenges with a long-term perspective, ensuring that bold decisions are balanced with responsibility and aligned with the company’s core values.

At Castalia Group, Andrew has built a culture of empathy, trust, and autonomy. He values the growth and success of his team, empowering them to excel independently while always having the support they need. His leadership is not only about business results but also creating an environment where people can thrive, leading to sustainable success.

Driven by a belief in legacy, Andrew is focused on building businesses that endure, mentoring others to think beyond immediate gain, and empowering future generations to navigate challenges with resilience and independence. Through his leadership, Castalia Group continues to grow as a values-driven organisation focused on long-term sustainability.

His trusted relationships have been instrumental in ensuring the long-term sustainability of the businesses he advises, where his efforts have positively impacted shareholders and clients alike. Aaron’s role as a shareholder advocate reflects his commitment to the Castalia Group vision. By prioritising relationships, financial sustainability and avoiding unnecessary risks, he has ensured Castalia Group remains comfortably independent and adaptable, enabling swift decision making and continued success.

Balancing his professional achievements, Aaron places immense value on family and personal growth. Together with his wife Chelsey, Aaron has cultivated a life rich in experiences, anchored in strong values for his children (Lottie & Jake). Drawing on his own upbringing and life lessons, Aaron strives to instil creativity, resilience, and a sense of purpose in his children.

Aaron is a lifelong learner, driven by an innate curiosity and a commitment to continuous improvement. Aaron believes every experience is an opportunity to grow and refine his approach, both personally and professionally. This mindset shapes his leadership philosophy, where every decision is guided by the pursuit of the greater good.

The ability to lead with optimism and empathy has earned Aaron trust and respect, inspiring his team to strive for excellence. His unwavering commitment to excellence, coupled with his belief in the power of positive relationships and values driven leadership, positions him as a driving force in shaping Castalia Group’s future.